WIGGLING 'LITE' IN GUEST MODE

[oldcrow]

So what has the Old Crow been up to lately? As getting crOwBX boards made for the euro and vintage replacement editions is largely a wait for the factories game I decided to do a project I had in mind for a long time, prompted by obtaining one of Dan Alich's awesome DuinoKits. "This aluminum case would make for a great little synthesizer enclosure," I thought to myself. "I think it is finally time."

Time for Crowminius. My take on the minimoog built as a single board synthesizer that fits into a DuinoKit case. Every control and jack found on the mini is likewise found on Crowminius. MIDI, dual LFOs dedicated to oscillator PWM, the Power Supply That Does Not Suck(tm). All here.

I blogged about it in its nearly-completed state:
https://blog.adafruit.com/2015/03/23/crowminius-a-synthesizer-story/

And the finished unit:



And of course, an audio demo.

http://www.cs80.com/crowminius/CrowminiusDemo01.mp3

Come to AHMW and see it in person!

Enjoy,

Crow
/**/

[Don T]

[oldcrow]

TL;DR FAQ:

The circuit board is 8.5" x 11" (216mm x 280mm), the size of the DuinoKit Essentials PC board the aluminum case of which settled the form factor goal for the Crowminius project.

The green things are some 3D-printed shelf clips I made that serve as makeshift pitch/mod levers. I will print better ones meant for this.

There are three LFO LEDs, two are behind the PWM pots (top middle), the 3rd shows the rate of the control osc. and is over by the pitch/mod wheel pots.

The vactrol/LDR is for MIDI modwheel action, which is kind of experimental at the moment.

The A440 reference is not a Wein bridge sine oscillator, but rather is a DDS table-lookup PWM sine tone generated on the MIDI microcontroller.

There will be USB MIDI, once I figure out how to do it. I rigged the hardware as per the V-USB spec but I am not a C programmer by trade. But, eventually.

The power supply will run on a single 12VAC, 250mA wall transformer. The power supply that does not suck mode involves the use of two 12VAC wall transformers so as to provide full-wave rectification.

The DAC is scaled to provide 5 octaves, F1 to F6 over a 4.096-Volt range. The DAC's 2nd channel will operate the filter cutoff for assignable key velocity or whatever.

I did not use ua726s as they are a pain to get and the thought of exposed parts heated to 80C meant someone would get burned. LM3046s are fine; there is a tempco resistor under the three arrays for the VCOs.

The filter resonance pot is in fact a 50K reverse-log type, but I provided for using a linear pot+resistor to cheeseball it.

Yes I will be offering bare boards. They will be $100.00. I have to correct a few cosmetic issues (mostly reversed knob and switch actions) but every part came from Digikey, Jameco, Mouser or Small Bear.

More later.

Crow
/**/

[indigoid]

That sounds bloody excellent.

[andrewF]

[home_listening]

Nice!

Anyway it can be easily mounted behind a panel (without running wires for the switches and pots?)

[Dogma]

OH this is gonna be fun. This is what its about taking classic architectures and seeing what happens....

I love the demo and Im a PWM freak so more demos of that if possible would be great....

So is it meant to be a voice or a whole synth?

Detuning sounds lovely BTW not too much beating or any really

[Dogma]

EDIT: There will be USB MIDI, once I figure out how to do it.

Very nice as theres the synth tech, ES FH-1 et al coming out so this just makes it that much more useful...

Is it class compliant midi?

[mig27]

Wow - what a project!
Tipping my hat.
Subscribed.

[sammy123]

What is AHMW? Is that a synth meetup?

[Adminius]

I understand that you're going to make the PCBs available for DIY, but will there be any completely assembled systems available?

Build a Eurorack version of this and you'll be hailed as a synth god (or at least a minor synth deity; "Crow, the god of LFO's").

[ThecureForSin]

[andrewradtke]

That sounds really nice. I might have to build one of these...

[Chrutil]

It's great that it has a power supply that doesn't suck!

[Reality Checkpoint]

Crikey Moses!

I shall watch this with interest........

[logicgate]

Awesome!

You made the chords by multitracking or there's a paraphonic mode?

[monstrinho]

Silly question, probably, but is this designed to go behind a panel or sit, umm, naked, as-is? The angle of the photo makes it really difficult to judge the size of certain parts (the big knobs look like they're towering over the Davies 1900s, for example). Also curious what the four patch points are for...

[mbroers]

jeeeeeez! NICE!

[oldcrow]

I wasn't thinking of a panel as the board mounts in an aluminum case that has a cover, but if I can devise a method to mount the small switches up higher on solder-in tiers, use pots with longer shafts and relocate a couple jacks some sort of panel could be used. --Crow

[oldcrow]

From what I can tell from the V-USB page it is a fully compliant USB 1.1 scheme except for some error handling. --Crow

http://www.obdev.at/products/vusb/index.html

[oldcrow]

I might make an SMT/pre-assembled unit, but that is down the road. I have crOwBX in Euro coming out later this spring so my SMT stuff is dedicated to that right now. --Crow

[oldcrow]

There are three oscillators, I just tuned them to a major and faded each one up with the on-board mixer knobs. That whole demo is just me flipping switches and twiddling knobs with the other hand on my MIDI master keyboard. The output goes through my mixing desk and into Ableton Live with one loop send/return to my Lexicon reverb.

Crow
/**/

[oldcrow]

I made this board to fit in an aluminum attache case similar to that used by the DuinoKit:

http://duinokit.com/storefront/index.php?id_product=22&controller=prod uct

In fact my case is from DuinoKit, I bought an empty one for this prototype, and will be arranging a bulk purchase.

The four small jacks are external filter CV, external pitch CV, external loudness (footpedal) and a switch trigger input. These four jacks are 3.5mm types in order to fit at all.

--Crow



/**/

[oldcrow]

This is a whole synth. It is not really set up to act as one voice in a polyphonic like crOwBX is. Of course you can just use four of these and dial in the same patch and use a MIDI key assigner. --Crow

/**/

[oldcrow]

Yes, now in its 15th year, I think.

http://165.138.219.1/~drew/ahmw/

--Crow
/**/

[nvining]

Oh, that sounds lovely.

Any chance of getting the Power Supply That Doesn't Suck as an Arduino shield on its own (in some form or flavour?) It would be VERY nice for prototyping things to have a good +/-12V (or whatever we're running on here) power supply, and an Arduino, all on the same board.

[JohnLRice]

Impressive work Mr. Old Crow sir!

[brother303]

Indeed, very cool!

Respect!

[seepaxton]

This sounds excellent!! How do you rate the build process, would you say it a particularly hard build?? Is there lots of matched transistors and tempcos to worry about

[nidas]

Awesome ! Looking forward to start with this.

[oldcrow]

The build, while tedious, is not bad. There are no esoteric parts here, except possibly for the reverse-log taper pots and those are at Small Bear and other vendors. There are three surface-mount temperature-compensation resistors which I got from Digikey. These are the only SMT parts on the board, and I provide through-hole pads as an alternate. The four LM3046/3086 transistor arrays are the only matched transistors.

--Crow
/**/

[ThecureForSin]

What's the footprint? Just considering an actual case. Or if you'd be kind enough to share the file for your top layer to get all position....

[oldcrow]

It is 8.5" x 11" (216mm x 280mm). I use a small aluminum attache case similar to http://www.aliexpress.com/item/Spring-2014-Aluminum-Frame-Briefcase-Fa shion-ABS-Solid-Portable-Men-Attache-Case-Portfolios-Organizer-Men-Bri efcase/1797514832.html

I have a wooden insert in the case to mount to board.

--Crow
/**/

[ultravox]

If I didn't already own a Voyager I'd be all over this!!

Nice work Mr. Crow!

[tIB]

Outstanding!

[timothyjr]

oh wow yesssssss. between this and the crOwBX you're getting me very excited.

[gwaidan]

Lovely demo-sounds very promising!

[Noiseconformist]

Great project, as always!
I'd love to hear some percussive sounds across its audio range, recorded completely dry.

[General_Dimi]

Killing it! Very nice, looks like a fantastic excuse to get into more DIY stuff.

[msghmr]

When can we buy a board?!?!

[oldcrow]

I am finalizing the board revisions to submit at the end of this week. I figure they will be back from the board house mid-April. I am currently building online BoM lists at Digikey and Mouser to make a parts order more efficient.
Total for the parts from Digikey/Mouser is just under US$190. More later.

--Crow
/**/

[colorbars]

$190 for parts, $100 for pcb... A minimoog for under $300

[crustibooga]

Tasty - very tasty!

[paulstone]

Great project
interested in making one

[Dude163]

Ill get one!

Will the PCBs etc be available in time for my 50th bday in July!

cheers

D163

[Altitude909]

outstanding. a DIY moog project of this scope is exactly what the world needs.

[latigid on]

And funnily enough, not one but two!





https://www.muffwiggler.com/forum/viewtopic.php?t=126711


The version of M. Delgoulet seems to have the more traditional layout, no offence to M. Crow but the knobs look a bit too tightly spaced?

[mOBiTh]

[oldcrow]

I'd heard of this, one reasons why I didn't go for a euro-style build on Crowminius. I had a different idea in mind, which is the great thing about DIY.

My controls are tightly spaced, a constraint of the aluminum case that got me to devise this thing. In practical use I've not found it a real problem though. I wanted a portable, self-contained machine and here it is.

I might make a larger control panel board that would connect to the main board through friction-lock headers for each control position except the rotary switches which would need harnesses. We'll see. I need to get rev1.1 boards stocked first. --Crow

/**/

[oldcrow]

I'll have them in mid-to-late April. Working out the final entries of the online shareable project BoMs at the moment. Folks will be able to login to Digikey, select my Crowminius v1.1 BoM and order it. Same for Mouser. --Crow

/**/

[Microscopial]

Oh yes please indeed

[oldcrow]

There are a few extra costs to consider, such as the case, a wall transformer (unless folks are like me and have a couple hundred of them) and knobs. I was able to effectively get mine built for $300 but I ordered enough parts to build five which brought the average down a bit. Still, with shipping costs and the hardware mentioned above factored in, I see a single-unit cost being US$350 max. complete as shown above. My firmware will be free with sources on github once I am done with the initial version. --Crow

[Shoggoth]

Wow. Sounds amazing and cost is right.

[amnesia]

This looks great. Without going through all the pages here, will there be a faceplate?

[oldcrow]

I might try to make something, but it is not high on my list at the moment. When I have final specs on the rev1.1 board I will provide a part placement file for the board-mounted control positions.

I use Alpha 9mm pots at the moment. To allow for a panel I'd need to use a longer pot, such as http://media.digikey.com/photos/Panasonic%20Photos/EVUF%20NO%20BUSHING %20SERIES.jpg

The main issue at the moment is getting Mouser or another vendor to quote me the Alpha SR2513-type bottom-mount rotary switches, which have the switch shaft coming up through a hole in the PC board. I've already provisioned for this in the artwork, I just need to get a buy in on the switches. --Crow

Other folks might want to make a larger breakout control panel and use pin headers for most of the board control positions. Go for it.

--Crow
/**/

[Dude163]

Thanks for the info OC!

so you could use a pot on a separate surface and just use wires to connect to the PCB? Like if I make a case for it I meant


sounds amazing

[jheronymo]

massive, i'm so sold! keep up posted!

[oldcrow]

Yes, mount pots and switches to a panel and 3-pin friction-lock headers, 2mm for the small switches, 2.5mm for the pots and manual wiring for the rotary switches. --Crow

[Dr. Sketch-n-Etch]

I just listened to the demo. My god, that thing sounds amazing! I think I want one.

[oldcrow]

Listening to my 1977 Star Wars Album by the "Electric Moog Orchestra" I've decided to cram one more thing onto this board. An S/H mode for modulation source. LF398-type as I did with my MonoPoly years ago.

http://www.oldcrows.net/~oldcrow/synth/korg/monopoly/shmod.html

On Crowminius a new switch crammed in between the OSC2 and OSC3 frequency interval pots will select red/pink noise (original) or clocked red/pink held samples to the noise side of the mod mix pot.

I blame this track from my album specifically.

https://www.youtube.com/watch?v=WVaoeX3ZDMw

Proofing of all my revisions to correct minor mistakes tomorrow, then I submit files for manufacture. --Crow

/**/

[koobraelc]

[grenert]

Amazing work, and tremendous generosity in making this project so ready to go (no part-sourcing troubles!).

This is a DIY dream!

[wavydave]

I don't know if I should get one anymore since I just found a Minimoog at an estate sale a couple of weeks ago for $35. Too bad that it was broken because it only played one note at a time.


April fools.

[revtor]

Damn Wavydave, I was about to shit my pants….

those deals are still out there Im sure!

~Steve

[oldcrow]

April Fool or not, that poor mini needs some serious TLC.

[oldcrow]

Reviewing rotary switches, I will caution now that I have sized the six switch positions for a Alpha SR2512F-series 2-pole, 6-position PCB mount part. I notice a number of these offered for sale on ebay and aliexpress that have the common pole pins on a different angle offset than the part number I am specifying. The full part number I use is SR2512F-0206-19R0B-E9-N-W.

While I expect the switches from China online retailers work fine, their mechanical fit might be a minor issue as the lobes of the switch would orient at a different angle than expected, meaning some resistors may need to mount on the board's underside to avoid the switch body.

By the way, C&K switches will not fit. Those use a 22.2mm dia. contact pin outer ring and a 7.7mm wiper pin inner ring. Alpha switches use a 20mm outer ring and an 11mm inner ring. Of course, off-board panel builders can use whatever they want.

FYI,

Crow
/**/

[sk23]

Thank you for the awesome project!

I'm really interested in it, can't wait as when will be available for purchase!

[radar]

can't wait !

[shimoda]

Looking forward to being able to order this one!

[oldcrow]

Another small cost detail, I did not include the price of the LCD. The LCD is optional but if used will allow some MIDI front end settings to be changed/displayed. I use this one: https://www.adafruit.com/product/772

I've not tried the supercheap ones from places like aliexpress yet, but they *should* work. The only caveat is if their board size is close to what I provisioned for on the Crowminius MIDI corner area. --Crow

/**/

[Captain Sternn]

Sounds awesome, definitely interested!

[oldcrow]

OK, for the initial board batch I will have 25 bare boards available. These are rev1.1 incorporating all the minor corrections I've made to rev1.0. For this first batch only I am offering the board at 20% off the $100 price for a final price of $80 (plus any applicable taxes) plus shipping. These boards are expected to arrive on 4/17/15 but I have opened up a pre-order for them on my shopify site. http://www.cs80.com/crowminius

--Crow
/**/

[oldcrow]

Note: this offer is only being posted here to Muff's. It might make it to other sites indirectly, but Wigglers get first notice.

[phutureboy]

My ! are you not some kind of living machine ?
Also can't wait to hear some good news about the crOwBX in Euro....

[medbot]

Hi Crow, do the bare boards come with the ATMEGA328P chip that's needed for MIDI? Sorry if that's a silly question, but I wasn't sure if there needed to be something from you with a custom firmware flashed on it or if I can just get one from Mouser.

[oldcrow]

The Atmel chip is a line item in the Digikey BOM I provide. This is of course an unprogrammed chip, but you can either 1) have someone use an ISP programmer or Arduino Uno rigged as an ISP programmer to program the part, 2) I plan to sell a pre-programmed part for $5.00 on my site or 3) the microcontroller is not strictly needed as the CV and GATE jacks work off pretty much any 0.8V/Oct to 1.2V/Oct MIDICV unit when the Crowminius is scaled for it. The only thing that would not be available other than MIDI control is the A440 reference which is generated on the microcontroller.

/**/

[medbot]

Great, I was about to pick up a board but don't have a way to program the chip so I'm glad you're going to offer them. I'll go ahead and pay for the board now and maybe the chips will be ready to go when the boards arrive and they can all be shipped together.

[wavydave]

Hey look! I just found some burning money!


So I bought two pcbs...

[grenert]

[wavydave]

By looking at the silk screening, were you trying to do an Oberheim-ish paddle on the LHC?

[oldcrow]

I use the Adafruit board as it uses a Microchip MCP23017 I2C I/O expander chip and their LCD library so as to only use two pins. I am not a C programmer (assembly forever!) but the statements to operate the LCD are pretty simple. Stuff like

lcd.begin(16, 2);
lcd.setBacklight(TRUE);
lcd.print(F("Crowminius v1.1"));

and so on. --Crow

/**/

[oldcrow]

I was just trying to get things to fit. The pots actually best install with both pointing to the left. I left a set of holes for the pitch pot to try and use a length of spring wire to make a "return to center" loading scheme.

I will be trying to make some printable wheels/levers is a 3D CAD when I have time. --Crow

[Altitude909]

[modintx]

Just ordered PCB - Thank you oldcrow for offering them. This will be a very interesting and fun build I think, can't wait

[oldcrow]

That is just it, I didn't have the 7 pins needed to operate the LCD directly, never mind the 5 pushbuttons.

There is also a 4-pin header for mounting the display away from the board, such as to a panel. The LCD is optional in any case. --Crow

[ElSmurf]

First post here. Very excited about this project, but I'm not sure I'll get my PayPal balance up on time to get a board from the pre-order deal, so I wanted to know if you have any idea as to when the next batch could be ready?

Also, you mentioned on Synthtopia that there are already people working on a front panel of sorts, I'd really like to get in on that. I'm the guy from the Yocto enclosure group buy, and I'm thinking about making a face plate design, to be made by Schaeffer/Front Panel Express, to mount on a standard Hammond enclosure.

[wavydave]

I missed your Yocto enclosure order for the same reason. Maybe we can work something out with Scott to ship you one of mine. I am at work right now. PM me to discuss this option.

[colorbars]

Where/how do I preorder?

[Reality Checkpoint]

[colorbars]

Thanks!

[oldcrow]

Various folks say they will fashion panels, we'll see. The only panel I might make is a small one to fit over the main board's control area such that it still all fits in the aluminum case. Off-board panels will need cabled to board headers (or direct-soldered) but nothing extravagant.

I imagine the next board batch will be early May. --Crow

/**/

[oldcrow]

Except for the aluminum case, mounting hardware and external AC wall transformers, here is every part needed. Note this is the general online BoM. I will also provide specific Digikey and Mouser uploadable BoM sheets to make ordering relatively quick. Of course no one is required to use these vendors; I just provide my project BoMs for them as they are where I order (digikey is a 1-day ship time to me).

https://docs.google.com/spreadsheets/d/1luph-CsIEe5RU8KX1xj2FkDNPgh8RL KgIt0w2aR_KPU/edit?usp=sharing

Cheers,

Crow
/**/

[Altitude909]

Weird board size but I found a candidate:

http://www.hammondmfg.com/pdf/HWCHAS1710BK.pdf

[ElSmurf]

[Altitude909]

1456RL1 would work but is huge, I have my MB808 in one of those and it's a beast. The other one isnt tall enough (6" flat front)

[medbot]

Crow, will the midi interface also handle pitch and mod wheel data from external controllers or is that limited to the pots on the board? Man, I'm psyched for this.

[oldcrow]

Eventually. The modwheel over MIDI sort of works already although to use it I have to open the local modwheel pot a little. Pitchwheel over MIDI I have not programmed yet but it is a little easier as that is just modifying the note data sent to the pitch DAC channel. The microcontroller code is a kind of work in progress at the moment.

The MIDI front end is not required at all, by the way. The CV and gate jacks can be used to bring in any 0 to 5v pitch CV from 0.8v/oct to 1.2v/oct; you have to set the scaling trimmers locally of course. I even included the legacy "switch trigger" input, although I use a 3.5mm jack and not the 2-pin Cinch Jones connector Moog used. For folks installing this board in a case where you have room to put jacks on the rear apron, you can use a Cinch-Jones socket if you really want to.

Crow
/**/

[mmarsh]

Hi Scott -

Just pre-ordered a board, pretty cool this will be a fun project and a great synth to boot.

PS - Don't know if you remember me from the old MOTM days, but a big howdy in any case!

Mike

[oldcrow]

Yep, I remember MOTM folks. I still make some 5U modules on request.

[oldcrow]

All boards now pre-ordered!

I might have a few more from the overage (they send a couple extra if one or more has a blemish), but there is no guarantee of this. If I end up with extras I will list them, but that would be it for batch 1. Batch 2 I will order once I build a rev1.1 to double-check things. --Crow

[fomtoberheim]

[oldcrow]

Found a minor issue, I still had a couple resistor locations with the incorrect value. I've updated the BoM. Batch 1 boards will have the mis-marked values, so take note.

[oldcrow]

Hey folks, batch 1 boards are here! I am shipping six parcels per day this week until they are all sent. I have AHMW this Saturday followed by a few days at my workshop back east (crowbx board manufacturing) but I should be able to get batch 1 orders all done before the 18th. I will be sending order shipment emails as each one posts, with a tracking number.

The rev1.1 BoM is online here,

https://docs.google.com/spreadsheets/d/1luph-CsIEe5RU8KX1xj2FkDNPgh8RL KgIt0w2aR_KPU/edit#gid=0

I will have pdfs of the schematic and a component placement overlay up on cs80.com in the next few days as well. I will be writing a build guide, but I have to build a rev1.1 and document the process as I go. I will be able to do some of that this week but the rest will be after the factory trip.

If I have any overage boards to sell, I will announce that here after the firm orders have shipped. It looks like I might have 1 or 2, I have to count up the quantity in the board stack I've not unsealed yet to be sure.

Cheers,

Crow
/**/

[medbot]

Sweet! I've been getting parts orders together all evening, can't wait to get it all together.

[medbot]

Oh Crow, do you think you'll have programmed MIDI chips to ship with the boards or are those not ready yet?

[oldcrow]

I can offer the programmed MCU as it is now, which does fine over DIN5 (classic) MIDI. I do not have any spares at the moment but I will order some in.

I've been tweaking a couple resistor values to try and make the octave selectors track a bit better, otherwise things look good.

[medbot]

[oldcrow]

You can contact them through their live chat and have line items added if the order has not shipped yet. I do this all the time.

In this instance you want a couple 6.04KXBK-ND resistors. I am trying to improve the octave selector ranging a little. --Crow

[samuraipizzacat29]

I'm in for round 2. I'd rather buy $20 extra for no parts subs

[InfraXpert]

Please, count me in for round 2

[sk23]

Please count me in for round 2, I want it!

[keganspence]

Totally down for round 2 as well!

[medbot]

The enclosure I'm using is about ready for a coat of Authentic Black Moog Paint (tm)...



I tried to keep it as Minimoogish as I could but had to take some liberties. Should still fit the Moog style knobs Smallbear sells with plenty of wiggle room.

[ElSmurf]

[cleaninglady]

I'm in for round 2 , let me know.

[Altitude909]

Hows the panel layout coming? Look for something basic like what pot does what for now

[bitflip]

[Altitude909]

Looks like the hammond CWW

http://www.hammondmfg.com/dwg16_CWW.htm

[medbot]

The enclosure I used is a 1456PL3WHCWW from Hammond. Here's a link to the page with the different models from that series - http://www.hammondmfg.com/dwg16_CWW.htm. They've got the same thing without the wood panels for a bit cheaper. I bought mine from Allied Electronics here in the US (I must live down the street from them, it took less than 24 hours to get delivered :0).

The PCB came in the mail as I was typing this

[oldcrow]

Tomorrow (Friday 4/17/15) is the final day this week I will be mailing boards out. I have AHMW on Saturday and I continue on to my factory afterward to work on crOwBX voice board production, so the next dispatch of boards will be from the local post office there on Monday. --Crow

/**/

[medbot]

[wavydave]

Mine showed up today, too. Yeah!

The YouTube unboxing video was here but I had to cull it.

[P_Carroll]

Count me in for round 2 as well. I showed this to my daughter who is the music major and I wil be building it for her.
For humors sake all I could think of was this image.

[lowell513mx]

I'm keen for a board from batch 2. I live in Australia now and it was difficult to grab one the last time because of time difference. Hoping for a chance this time.

[oldcrow]

For the next round of boards I will have more than 25, probably 100 pieces. Please note as stated earlier in the thread these standard issue boards--that is, boards after batch 1 of a revision--will be USD$100.00 each. I will order boards after I build a rev1.1 to document the build guide, and that will happen after my trip to AHMW and afterward my factory to work on crOwBX voice card SMT manufacturing. Estimate early May for board availability.

FYI,

--Crow
/**/

[lowell513mx]

Perfect, thank you for your time and dedication. Cheers!

[monkeyssj1]

So stoked!!

[sk23]

So if I understand right, on early May will be available a stock of 100 boards rev 1.1?

[fomtoberheim]

[colorbars]

Is there a mouser BOM available for this yet?

[Henfield]

I had the good fortune of checking out the prototype at the AHMW meetup on Saturday, as Old Crow brought the prototype with him. It sounds amazing!! I can't wait for boards to be available again, and for built units in the future!!! We compared it side by side with an actual Minimoog, and this little clone held its own!

[nickster]

[oldcrow]

I am currently at atelier Crow in WV working on crOwBX voice cards. I'll post a short video of the L60V in action on the crOwBX thread once I have the program debugged.

I will provide Digikey/Mouser online or uploadable BoMs when I return to Chicago this weekend.

[nickster]

If anyone is considering offering a break out PCB for a larger faceplate that looks more like the original mini I would be very interested. A desktop mini is something I've been interested in for a long time but having gorilla fingers I'm hopeless with tightly packed synths. Even ones as beautiful and clever as the Crowminius.

[bartleby]

[medbot]

Hey Crow, I know you're out of town but maybe you can help out with this real quick. I've been stuffing the board and it looks like there's a discrepancy with R116 and R131. On the BoM, R116 is listed as 4.02k and R131 is 5.2k, but on the board they're reversed, with R116 showing 5.2k and R131 showing 4.02k. You don't happen to remember which is right do you?

[oldcrow]

Oops, another refdes swap I missed. R131 is the 5.1K, which goes in the place marked R116 5.1K. R116 is the 4.02K which goes below the 5.1K (marked R131 4.02K). I have noted this in the BOM. Thanks, Crow

[Brunstein]

This keeps popping into my head since I first learned of it. Definitely interested, funds permitting.

[medbot]

[monkeyssj1]

That looks wonderful!

[sk23]

Hello,
I just bought the rev 1.1 batch 1 pre order and I wouold like to be sure to have the latest BoM for this.

Where I can get it?

I also saw the BoM and the pots are 2 cm tall , so I wondering if it's possible to have longer alternetives to use with different knobs of the prototype.

Thank you

[medbot]

I stared at the board for more than 30 minutes last night and just can't for the life of me find the KSP-55 transistors. Those are the last two passives I need stuffed, so if anyone can spot them and let me know where they're at I'd be grateful.

[modintx]

I just had a quick look as well - nope - however they may be labeled as T vs Q on the silkscreen. Do you have a T16 & T17 unpopulated on your board?

Just a thought

[medbot]

Thanks for looking. I checked T16 and T17 but they are both silk screened as 2n3904s.

[modintx]

Me thinks we need the schematic then to trace it down - did old crow post that yet?

This build is further down my queue so haven't been watching thread carefully sorry.

[oldcrow]

Hm, the KSP55s shouldn't be on the v1.1 list, they were not needed.

[Dimitree]

just in case someone is looking for switches that looks like the original minimoog, I have some for sale:
http://www.ed-sounds.com/switches.html

[medbot]

[oldcrow]

I just got back from my week-long trip to my workshop to make some crowbx voice cards. I will resume crowminius board shipping on Monday. I had hoped to send some out while there, but I was just too busy: 16-hour days.

To answer your question, you can just put a 25K trimpot in there and preset the default pitch. --Crow

[aburrows]

This is such an exciting project! I’ve been following the posts on a daily basis to see what the community is doing and eagerly awaiting the latest updates from Old Crow.

A panel mounted solution is definitely what I’m interested in. Medbot, your case and board are looking great. I was also considering the use of a Hammond Mfg. case and compiled a list of some options that seem to accommodate the dimensions of the crowminius board:

http://www.hammondmfg.com/pdf/HWCHAS1710BK.pdf - can get this version a little wider at 20” also
http://www.hammondmfg.com/pdf/1456RL1.pdf
http://www.hammondmfg.com/pdf/1456PL3.pdf
http://www.hammondmfg.com/pdf/1456PH1CWW.pdf - too small by .2 inches. Bummer, love the wood sides.
http://www.hammondmfg.com/pdf/1456PL3CWW.pdf
http://www.hammondmfg.com/dwg20CWW.htm - wood sides and black finish. Only negative is no sloping front. There is an option that is 17W x 10D x3H. Would need to order the appropriate bottom plate as it’s not included. I found it listed for $71 for main case (not including bottom plate).

I’d love to see someone get really ambitious (not me!) and go full out on a mimimoog style case. Check out the Anicontrol build video and project page for inspiration. Just omit the iPad and drop in a Crowminius!:

https://www.youtube.com/watch?v=kXcIDzRtsJI
http://www.synth-project.de/animoog.html

I noticed you can get parts to build a dedicated keyboard at Doepfer. They offer Fatar keybeds and midi modules to control keys, pitch bend, etc.

http://www.fatar.com/home_fatar.htm
http://www.doepfer.de/MKE.htm

I’ll be aiming for a more modest stand alone box as mentioned above. Mining older posts on this thread, looks like the approach that best suits the case designs above would be to panel mount all pots, switches, midi, audio jacks, etc. Anyone who’s taking this approach, I’d love to see and hear about what you’re doing to make it work. Crow has suggested pin headers for everything but the rotary switches, which would need to be manually wired. Love any input on parts used, pics of completed wiring/boards, etc.

In the meantime, I’ll be eagerly awaiting the next round of boards! Thanks Old Crow for the awesome work here.

BTW, I had my old OB-Xa stolen after a show about 20 years ago and with the prices so insane these days, I don’t think I'll own one again. I’ll be looking at the Crowbx next

[medbot]

I didn't get as far as I wanted to this weekend, but here's where I'm at with the wiring so far. The big stuff (the rotary switches, most dpdt switches) are wired on the board side and I've just got the mixer pots left and that's all of those. Haven't even started on the jacks, power, MIDI, or ground bus yet yeesh. The rotary switches were a minor nightmare because the pad holes are kinda small and the wide ribbons of stranded wire I was using were fraying like crazy. It's Smallbear bonded wire or bust for me from now on.

[nickster]

Spaghetti! Fast work though medbot. Very interested to see how this turns out as I'm aiming to go down a similar route. Still hoping for a break out board though to help ease the pain.

[soderstrom]

Oh yeah, Rock 'n' Roll!

[setsun8]

medbot are you using 24AWG? or what thickness fits through the holes?

[medbot]

[setsun8]

Thanks for the info! I am about to put in a Small bear order so this is very helpful.

[oldcrow]

Btw, got my Davies 1900H clones from Ali Express today. 100pcs at 26 cents each. They have pretty much any color, and other knob variants.

FYI, Crow
/**/

[AlanP]

They look like Tayda's 1900H knobs, which are quite poor when it comes to set screw thread stripping. I'd be quite interested to know how you get on.

[oldcrow]

Errata: I noticed that on v1.1 for R101A, the value is marked 2K32 1% whereas for R23 and R63 (the same resistor in the first two VCO front-ends) is marked 23K2 1%.

The thing is, both are correct, provided:

1) The three resistors are all 2.32K or 23.2K
2a) If they are 2.32K, R24, R64 and R102 are 100 Ohm 3300ppm tempcos
2b) If they are 23.2K, R24, R64 and R102 are 1K 3300ppm tempcos

Just a heads up so everyone has the same VCO scaling for all oscs.

I have noted this in the BoM.

--Crow
/**/

[sk23]

[oldcrow]

The BoM is online as a google spreadsheet:

https://docs.google.com/spreadsheets/d/1luph-CsIEe5RU8KX1xj2FkDNPgh8RL KgIt0w2aR_KPU/edit?usp=sharing

I update it online as needed, so an occasional refresh is suggested.

[medbot]

Getting closer...

[nickster]

Crows nest! Looking good. This kind of Deep Wiring Voodoo is clearly not for the faint hearted!

[mOBiTh]

[Dude163]

ANy word on when the batch of for sale PCBs will go up?


thanks Scott

[oldcrow]

I am building a rev1.1 right now, to verify everything tweaked from v1.0. Once this is done I will order a new board set. At this time it looks like the order will go in next week. --Crow

[sk23]

Can't wait!

[ElSmurf]

[The Big Ear]

[aburrows]

Can't wait for new rev. Thanks for posting update Medbot. Gives us a sense of what will be needed to wire to a panel, which I know a lot folks have expressed interest in doing.

[medbot]

[oldcrow]

Hey folks, I have five pre-order boards left to send out. These will go out on Monday (5/4/15). The past week was a busy one that had me driving 3 hours to Robert Rich's excellent concert at the Peoria Riverfront Planetarium yesterday and today is all taken up with the wife's birthday. I might get back to assembling my Crowminius v1.1 tomorrow.

[SyntheticDetroit]

Excited to Build this. More excited to play. I am thinking I am going to go the route of mounting the pots/switches to a panel and do runs. A question that came up in my mind was would it be possible to have a variable wave shape pot instead a fixed position? what would this take besides a multi input pot? How great would it be to assign the new pwm lfos to fade between waveshapes?

[medbot]

Well I finally had some time and got it all wired and it works! Mostly... Something's up with the noise, glide, and keyboard tracking, as none of them seem to be working, but I probably goofed something on the wiring. Other than it not being calibrated it sounds great and everything seems to work.



Hey Crow, were you planning on writing up a calibration guide or should I just go with the Minimoog calibrations found online? Also, any idea when you might have some of the MIDI chips available? Thanks for everything.

[oldcrow]

The waveshapers are not set up this way unfortunately. To do a gradient blend of waveforms from a single pot each osc would need a 4-channel interpolating scanner-type level control. I made the osc bank in the manner of the model D's, which is why the pulse outputs are the three fixed intervals (50%, 25%, 15%) with my added PWM for the pulse width shapers.

I will tinker with mods to the basic system at some point. --Crow

/**/

[oldcrow]

You can generally follow minimoog calibrations, except the guides I've seen tend to list the scale and zero adjustments backward: you set a scale trimmer on the low note, and the zero trimmer (I think they called it "shift" in the Moog docs) is set on the high note. The only real difference in the tuning is I set things up to use a 0 to 4V pitch CV over 5 octaves as the MCP4822 DAC uses a 4.096v internal reference.

I will order in some Atmel MCUs and program them this week.

--Crow
/**/

[sk23]

Hi Crow, can you kindly explain why the project contain a DAC? The synth isn't 100% analog?

And about the Atmel MCU, what's the use in the project?
Why we should program it, and how. The guide you will send us contain these info?

thank you very much

[medbot]

[oldcrow]

I put a MIDI front end on the board as there is no local 44-note keyboard as per the model D. This MIDI front end is completely optional as you can operate the synth from the CV/gate/switch trigger jacks. I mainly put it there for my convenience. The only thing not analog as far as the synthesizer goes is the A-440 reference tone which is a digital sine tone generated on the microcontroller.

The Atmel chip needs to be programmed, I will be stocking some for those who want them. Those who know how to load one can of course do their thing. --Crow

/**/

[sk23]

Ok thank you for the infos.

I bought the rev.1.1 batch 1, can you count me in for the Atmel programmed chip please?
Should be great if you could ship them togheter!

thank you

[nickster]

[medbot]

[medbot]

Hey Crow, I had a question about the two CV inputs. On the silkscreen it says that for 1v/o use J1, otherwise I guess it's only .815v/o. I noticed though that the .815v/o input is the one that goes through the glide and filter tracking circuits, so it's the one I would prefer to use. Can that one be calibrated to be fairly close for in tune playing with a 1v/o MIDI-CV converter? I'm about to start calibrating and will see for myself soon, but any input would be helpful. Thanks.

[oldcrow]

You should be able to calibrate it to 1V/Oct as-is. I only marked the board as a reminder as to how the MIDI front end operates. Worst-case you would need to change R4 to 121K, but I think there is enough headroom in the trimmers to go from 0.8v/Oct to 1.2V/Oct. I say this not having actually tried it, but the math works out. The only thing that might be tricky is the octave ranging as it does not have its own zero/offset trim. --Crow

[jackmattson]

Well done!

Digital oscs are the new analog filters.

My 2 cents: It needs a panel or housing.

I know you are showing off your synth, but you just resold me on the Lexicon sound

Bookmarked.

[oldcrow]

Just to keep this from getting confusing: the oscillators are the standard analog type as used in the newer revision oscillator board of the model D.
The filter/amp/EG are all fully discrete transistor circuits. The only digital portion is an optional MIDICV circuit that has the A-440 sine tone done as a DDS PWM waveform. Everything else is as analog as it gets.

[medbot]

I'm having a hell of a time getting this calibrated. Here's what I'm doing, let me know if there's something obvious I'm doing wrong. My MIDI-CV converter is well calibrated so we can at least rule that out. I omitted the pitch bend pot as mentioned earlier, and took your advice and replaced it with a 25k trimmer, which I've got set to just about 5.00v, so it should functionally be at zero detent.

Everything off but VCO1, set to saw, set to 8'. I start with a low A on my keyboard and use the scale trimmer to get it to sound an A on my tuner. Then I move up one octave to the next A and adjust the zero trimmer until it sounds an A. That changes the lower note, so I set it back to an A, which changes the upper note, and back and forth it goes until I run out of turn on the scale trimmer.

I think I'm supposed to be narrowing the gap a little bit with each adjustment, but it always seems like I wind up with an A#/B on the top and an A a few cents flat on the bottom with no more turn on the zero trimmer. Am I missing something simple or just plain doing it wrong?

[oldcrow]

What is the OCT1 trimmer set to during this? --Crow

[medbot]

I wasn't sure how best to check that because I can't get under it to check the wiper itself, but the resistor R19 that the wiper connects to is reading -3.34v.

[oldcrow]

Ah, OK. You should tune at 2' setting. High A (about 3.5v from the MIDICV) should get your 3520Hz by adjusting the zero trimmer (R14). Low A (0.5v MIDICV) should be trimmable to 440Hz with the scale trimmer (R16). Using
the 2' range takes the octave trimmer out of play. If you still can't quite get it to settle in R4 might need to be swapped out for a 121K. I have not finished my v1.1 yet, I will know more when I do. --Crow

[medbot]

[jackmattson]

[oldcrow]

Well, it looks like my setup for 0.815v/oct won't quite trim to 1v/oct. If you want to run it on a 1v/oct MIDICV change R4 (and R6, if you use the external pitch input) to 121K. Then it should tune up. I would have used a DAC with 5V reference (and a future rev might do this) except I have to install a precision reference as 5V regulators vary from part to part too much. I'll note this in the BoM.

[medbot]

Well it took all night, but I've got three oscillators that are nicely in tune across the keyboard in every octave. The resistor change to 121k for R4 and R6 did the trick and let me dial things in - I'm glad I wasn't crazy running out of trimmer turn before the swap.

A note for anyone building this - I definitely recommend multiturn trimmers for the zero trimmers at least. The other ones were fine with single turn, and it might even be bothersome to have multiturns on those since you'd have to turn so many times for otherwise small changes, but I very much wished I could be more precise on the zero trimmers. They've got a really big range and I did a lot of "it's -2 cents, now it's +2 cents, now it's -2 cents, etc." If I were doing it again I would also not get my cermet trimmers from Tayda. Most of them worked just fine but I had a few that seemed extra sensitive to even the slightest movements, making them a pain to dial in.

I haven't messed with the VCA calibration, and I might not since I'm not entirely clear on what it does and everything sounds and responds so good as it is. There's only a slight thump and I have to really crank my speakers to hear it.

I tried calibrating the VCF a little, but it seemed like a losing battle this late at night after all the other stuff. I'm ready to stop tuning things ha. I might come back to it or I might not.

The only bug I've noticed is that there is some signal bleed when I have the VCO mixer switches off with the knob turned up. I didn't use shielded cable for that and only realized I may have wanted to just now, but it's certainly not a deal breaker whatever the reason.

Other than that, this thing is killer. A friend stopped by while I was tuning it earlier and I played two or three notes (with only one VCO no less) with some filter contour and that was all it took to make him weak in the knees. I'll post some pictures and audio tomorrow or over the weekend. Thanks Crow!

[oldcrow]

Awesome, glad you got it sorted. This sounds like my fussing over the v1 when I first got it running back in March. I'll look into using multiturn trimmers with higher values so as to cover both the 0.8v and 1v octave ranging. That or I'll add a jumper and resistor to allow onboard gain tweaks without soldering.

[nickster]

If I was excited before I'm certainly hyper now! Glad to hear you managed to iron out the tuning issues. I am wondering if the thump you mentioned is similar to the TTSH issue (by design as on the original ARP2600). Perhaps this fix might be relevant, apologies if it is not.
https://www.dsl-man.de/display/DSO/TTSH+Mod+VCF+Input+coupling

On another matter I really hope Crow might consider a panel for this in the future.

[medbot]

[sk23]

Hello,
Medbot thank you for your useful posts that I follow everyday!

I have two questions regarding your issue, if we tune the synth with the midi input we can pass over the difficoulties you reported by using CV input? We still need to change the resistors?

About the trimmers, which R number do you suggest to replace with a multiturn one? Do you have suggestions for the sobstitute?

Crow when do you think to ship the rev 1.1 batch 1? I can't wait to start the project!

thank you very much

[medbot]

[sk23]

Hello Medbot, thank you again for your kind help.

Last question (I hope! ):

About the multiturns I found two sobstitutes, one with 4 and one with 25 number of turns, which one you suggest to use?

Thank you very much

[medbot]

[sk23]

Perfect thank you!

I hope that these info will be useful to others Crowminius builders

[oldcrow]

Here is a *large* image of the v1.1 I am building with all resistors placed, save for R9 & R10. I will take another photo with more even lighting as I want to show the resistor color codes as clearly as possbile, but this image is decent.

http://www.cs80.com/crowminius/Crowminius_Resistors_large_001.jpg

[oldcrow]

FYI, I use Bourns 3296-series for multi-turn trimmers, such as

http://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&keywo rds=3296Y-103LF

In fact the part outline I placed for all the trimmers is for a 3296. The 3362s just happen to fit there too.

[sk23]

Hi Crow thank you for the suggestion for the sobstitute!

I place an order on Apr 21 for the rev.1.1 batch 1 and now I see on your shopify that we can choose to buy in bundle with the board the pre programmed midi chip.

If want it too, how we can manage it? How we can get in touch directly?

PS: I would like to give my (marginal and not tech) contribution too, and I suggest to ones that are searching for Moog style knobs to take a look at www.banzaimusic.com because they have fluted knobs for really cheap!

[oldcrow]

I am in the middle of tinkering with the shopify site. A separate line item will be added for just the microcontroller IC. I'll have that online later in the weekend. --Crow

[r-led-boreh]

Speaking of bom:
1N4004FS-ND is not available in digikey, what is right #
3.3K 1/4W 5% axial resistor - has no digikey #, what is right #
493-12572-ND - the same story
R332XBK-ND - the same story

[sk23]

Hello, I was in the same situation and I found these sobstitutes, maybe Crow could validate them:
1) 1N4004FSCT-ND
2) I need it too!
3) 493-12572-1-ND

About n. 2 here a list of possible choices:
http://www.digikey.it/product-search/it?FV=4040e&k=3.3K+1%2F4W+5%25+ax ial+resistor&mnonly=0&newproducts=0&ColumnSort=1000008&page=1&stock=0& pbfree=0&rohs=0&quantity=&ptm=0&fid=0&pageSize=500

[oldcrow]

I updated the BoM:

1N4004 is Digikey # 1N4004DICT-ND
3.3K 1/4W 5% is 3.3KQBK-ND
493-12572-ND is actually 493-12572-1-ND
R332XBK-ND is actually 332XBK-ND

[r-led-boreh]

[The Big Ear]

I just ordered the PCB and chip. Really looking forward to building this.

Cheers,

[ElSmurf]

[medbot]

Have you guys looking at Banzai seen this thread?

https://www.muffwiggler.com/forum/viewtopic.php?t=131600

I'm working on some audio clips now...

[sk23]

I've just realized that the BoM's pot haven't a F type shaft, so we can't use Banzai's screw knobs?

[medbot]

Alright, here are about 22 minutes of random doodles and demos. These were all recorded totally dry and there are no external modulations - they're all one take recordings of just the Crowminius by itself. The parts that are on beat were sequenced with my MPC200xl, the rest was played through a Hex Inverter MIDI2CV and a crummy MIDI keyboard. Most of it is short little jams and basslines, but there are a few extended sections - one of note is a few minutes towards the end where I put the PWM Crow added through the wringer, while the long bit at the beginning features the S&H circuit throughout. Hope everyone enjoys them.

[setsun8]

wow, sounds really impressive dry, thanks for the demo. I also can't wait to see pics of your case .

[medbot]

Oh yeah, I meant to post a couple pictures too. It's about as nice as I could get it with a paint pen.

[r-led-boreh]

[r-led-boreh]

[aburrows]

Awesome Medbot! Thank you for posting the demo and pics. Your panel came out great. I'll be looking to do a similar setup. Congrats on your Crowminius!

[setsun8]

Thanks for the pics medbot , it looks great! I'm curious, what was the drilling done with? I am exploring my options for a case but my tools for drilling are limited so I may have to pursue other case options.

[sk23]

That is great Medbot! Nice work!

[ElSmurf]

Great stuff medbot! The crowminius really has the soul of the original, I can totally feel the seventies vibe in the demo.

Also, thanks for those pics of the front panel. It's going to help me a lot in designing my own.

*EDIT* I have 2 questions about your enclosure design :

- is the COLOR switch in the lower left corner for the noise color?
- to what is the LED above the Decay button connected?

[medbot]

[medbot]

[soderstrom]

Wow, good work, medbot!

[oldcrow]

Yes, a very good demo of the machine. It just goes to show what Bob Moog told me back in 2000~2001 was correct: the kinds of transistors do not matter so much as the biasing. I managed to retain the "secret sauce" that defines the minimoog sound (it concerns interaction between the filter and amplifier) while using just 2N3904s and 2N3906s. I blame Rohm and Panasonic for making thousands of different types of transistor model numbers when one really just needs maybe five types overall for just about anything.

[sk23]

Hi Crow
did you menage myshopify to buy only the pre-programmed midi chip?

For people who have already placed an order, can you consider to add only the chip without the spedition costs?

Or if you have another easy method (paypal?) to send you the 6$ let us know.

thank you

[monkeyssj1]

Where could I order said chip? I just ordered the board from the cs80 website, but haven't familiarized myself with the b.o.m. yet.

[sk23]

There was an option in the website:

http://ibin.co/21O19Me2hRWB

This chip is also in the BoM but need to be programmed.

[monkeyssj1]

gotcha thanks for the quick reply! crow i sent you a pm and hopefully i can paypal you the extra money and you can add the chip to my order before everything gets shipped out.

[sk23]

I'm in the same situation

Looking forward to hear news from Crow!

[ElSmurf]

medbot, thanks for clarifying. I did not however find an envelope led on the board, only the gate.

[sk23]

Speaking about the power supply, which brand do you suggest (like you wrote on the board "That does not suck" )?

Which are the correct V and A value?

Thank you

[samuraipizzacat29]

[medbot]

[sk23]

Thank you for the reply.

If I understood Correclty I need 2 wall transformers.

I have checked the links and I searched for them on different websites. Seems that are all running with 120V input (American) and not with 240V (European).

I thought If I Can use it anyway, carefully choosing the one which has 12V AC output.

Can Anyone help me?
Thank you

[ElSmurf]

@sk23, try looking for the Velleman/HQ Power brand, they have a 12VAC 500mA for 230V. Check with your local electronics store, they should have something like that.

I also wanted to point out that Banzai has the VTL5C9 in stock.

@samuraipizzacat29, the idea of using a transformer to drive the 2 12VAC inputs sounds like a good idea. I'm planning on building a fairly huge 50x24cm enclosure, so I'll have plenty of space for that!

[medbot]

[oldcrow]

I've been running my v1.0 for months now on a single 12VAC, 500mA unit. For many this will work just fine. --Crow

[sk23]

Thank you very much for the replies!!!

I share this adapter I found, maybe it could be useful to some european guys:

http://uk.farnell.com/ideal-power/77de-06-12/power-supply-ac-ac-10w-12 v-0-5a/dp/2368013

Just to know, if I want the "not suck" mode I can use two of these even if these are 500 mA each?


----

[oldcrow]

Yep, no problem.

[oldcrow]

The upcoming board batch is "in processing" with estimated ship date of May 20th. They ship via fedex so everything is on track for May 23rd.

FYI --Crow
/**/

[peAk]

So after seeing this thing posted up on a pedal building forum I belong to and listening to some of the Crow and Medbots demos, I said that I had to finally make the plunge into building synths.

I may have bitten off more than I can chew, being that I have only built guitar pedals…. but I needed something to WOW me enough to try and take on a synth build. This, obviously, was it!

Order placed!

[oldcrow]

I received my "processing" email from the board house, which usually means they're about a week out from delivery. FYI, Crow

/**/

[sk23]

Hi guys, talking about the BoM again, I didn't found these rotary switches in stock at Mouser:
http://www.mouser.it/ProductDetail/Alpha-Taiwan/SR2512F-0206-19R0B-E9- N-W/?qs=%2fha2pyFaduhTGI1219i84p2CaJQP48Fo0bR1CQwk5pcg4I5L9Pf8GQ%3d%3d

So I bought these with the same electronic characteristics:
http://www.mouser.it/Search/ProductDetail.aspx?R=SR2511F-0206-19R0B-E9 -N-Wvirtualkey14860000virtualkey105-SR2511F-26RN

But take a look at the shaft, it is totally round!
Which kind of knobs do you suggest to use?
I feel that the Moog's style ones that Banzai has (with the screw lock) will not work.

Thank you for the help!!

[r-led-boreh]

[ElSmurf]

[r-led-boreh]

[r-led-boreh]

[oldcrow]

I am preparing some docs for all this, it is just May is the busiest month of the year for me. Send a PM if you want a schematic. I hope to have the complete build doc sometime in early June. --Crow

[sk23]

Thank you for the infos about the rotary switches, I will build a panel and I will search around for some 6mm shaft knobs.

I have another question about the 15 slide switches, Crow chooses these in the BoM:
http://www.digikey.it/product-search/it?x=0&y=0&KeyWords=CKN9545-ND

But how we can use these on a panel? Looking the photo of Medbot I assume that he uses a different kind of switches, can you tell us "panel Crowminers" which one?

thank you!

[ElSmurf]

[sk23]

Yes I'm in Europe! Thank you very much for the infos again!

[ElSmurf]

I received a big part of my Mouser order today, so I started soldering the resistors just now. Like medbot said, this is some serious pro-level Where's Waldo. Especially for the highest numbers, they're all over the place. But it's a nice board to look at, and I'm sure once I get passed 50 or so resistors things will start to speed up.

It's very hard to put down the soldering iron!

[r-led-boreh]

[r-led-boreh]

[oldcrow]

I am in the process of adding a visual reference for every part value. Have a look at column G in the online BoM.

https://docs.google.com/spreadsheets/d/1luph-CsIEe5RU8KX1xj2FkDNPgh8RL KgIt0w2aR_KPU/edit?usp=sharing

I am filling this in throughout the evening.

--Crow
/**/

[Nargan]

I've been lurking here since before the v1 boards were available but I finally had to put in a preorder after hearing these completed boards' demos. I don't even care if the current v1.1 batch has sold out and I have to wait for the next order because this sounds great.

Looking forward to many nights of staring at hundreds of parts and a soldering iron. One question was that I believe it was mentioned that there are hole-thru options to replace the surface mount components. I see that option for R24A, R64A, and R102A on the BoM. Are there any others that aren't immediately obvious there?

[medbot]

[oldcrow]

Latest board batch landed in Memphis this evening. I *might* get them tomorrow.

[sk23]

Wow big thanks Crow! That's awesome!

[ElSmurf]

[oldcrow]

The latest Crowminius board batch has been delivered. Shipping will start on Tuesday 05/26/15. I have four boards w/Atmel MIDICV chip currently left in inventory along with 22 boards w/o the MCU. So if anyone was waiting, get em while they're here. Next batch order will probably be late June. I will get some more Atmel chips in to restock the combo SKU.

Back to making the visual parts placements...

Crow
/**/

[Padrat]

So I've been thinking about building one of these since Crow announced them. My main hangup to not doing this is that I'd like to integrate a 37 key keybed into a case of my design to make it a performance oriented instrument. Any suggestions on how to go about doing that? Also I've heard good things about Fatar keybeds, anyone have any luck with any other makers?

[oldcrow]

Getting a keyboard from Fatar is the hard part. Getting just a keyboard assembly from anywhere that does not involve cannibalizing some old machine is a challenge. I tend to buy old organs that are $50 or less mainly for the keyboard (especially the wonderful 1970s Yamaha keyboard actions) then use them with another version of my MIDICV circuit that scans a keyboard, similar to http://www.cs80.com/SSK/

[nickster]

Try to see if doepfer has something available. But I think 37 keys might no longer be available. Check out the ARP keyboard DIY thread by Kipling for more keybed details. As this project has MIDI you can always take a MIDI keybed and adjust for your needs.

[Starspawn]

[colorbars]

Bought one of the first run of boards but didn't see the option of the pre-programmed atmel chip... Any way I can get it seperately??

[ElSmurf]

I went a little nuts with the switches and got these from Mouser :



For anyone interested, they're NKK switches with part name M2022TNW01

They're bloody expensive for a switch, but I'm sure they'll look the part!

[nickster]

I like the way you are thinking with these switches. Part number noted thanks for sharing this.

[ElSmurf]

I have a question about R261. In the BoM both the description and part number state a 1/4W resistor, but the silk screen and surrounding resistors suggest a 1/2W. I ordered a 1/4W, can I solder this one in?

[thebot]

So I've been listening to too much Sun Ra this last couple of weeks and I couldn't resist any longer. Bring on the Mini!

[sk23]

Here! Daily check if will back in stock.

http://cs80-com.myshopify.com/products/din-midi-microcontroller-for-cr owminius

[oldcrow]

1/4W is fine. --Crow

[oldcrow]

I am starting up shipments a week later than planned due to a lingering illness (flu bug in May, go figure). I will process 6 per day in the order I received them as the international orders take a bit of paperwork. As each order is posted I will send out a shipping email through the shopify site.

--Crow
/**/

[nickster]

Good to hear, but no stress. Health comes first. Also had a flu bug these last few weeks. Sucks to be sniffling away when the sun is beaming down on you. Get well soon.

[thebot]

[Pioneers]

I just placed a Digikey parts order. It clocked in at about $130 with only 1 resister not in stock. Assembly should commence soon!

[ElSmurf]

[Altitude909]

I have to bow out of this and my rev 1 boards are up for grabs, $80 each (what I paid) shipping out of Michigan. PM if interested

[sk23]

Cool! Thank you for that!

I agree with all the things you would change.

Which kind of knob you will use with this panel? Which size did you consider?

[medbot]

[medbot]

Another thing - unless I'm way off the mark, some of the on/off switches (osc mod, filter mod, filter key) could also be replaced by pots, giving you a finer degree of control. It's not Minimoog authentic, but being able to send different amounts of mod to the osc and filter sections would be cool. If I was doing it again I would definitely have considered going that route.

[ElSmurf]

Thanks for the feedback guys, this actually helps a lot and I got some good ideas for the changes now. The knobs I'll be using are the synthie series from banzai, the big ones are 1.25", the selector knobs just over 1", the smaller ones are 3/4" and the 4 little ones are 16mm.

I did like the big knobs for the cutoff you used, medbot. I also like your idea of reducing the entire mixer and output sections to a single line, this way I can free up a lot of space for the osc and mod section, and line up the frequency knobs again. I'll just have to get over the feeling of blasphemy trying to improve the original design!

As for the panel and the housing, I'm going to start by having an acrylic one lasercut at Formulor, which I'll use as a base to hold the switches in place. Still looking for options for the actual panel - either I'll go with Schaeffer or have them done by re:synthesis, depending on the price and quality. And for the case I bought a lovely 9ft long beech plank to make a custom enclosure based on my Dreadbox murmux semi-modular, but sloped. So, still a long way to go!

[sk23]

I searched in Banzai and I found that knobs, for me the most Moogy style:

http://www.banzaimusic.com/Fluted-knob-FLUTEY.html
http://www.banzaimusic.com/Synth-knob-Synthie-5-Black.html
http://www.banzaimusic.com/Synth-knob-Synthie-1.html

Had you thought for these for your panel?

[medbot]

[colorbars]

Anyone have a mouser cart for this they'd be willing to share?

[wahee]

I think this is a fantastic development. Big kudos to Old Crow for all his hard work, enabling builders like me to develop a working synth at a reasonable cost. It looks like a bit of work but I have already had some experience in totally refurbishing my Prophet 5 so hopefully this will help in the build

Spent last night punching the codes into Digikey so I have just ordered a board from CS80 and half the components from Digikey. My plan of attack is to work on this in stages, basically by going down the BOM and ploughing through. I will order a minimoog style panel and fit the pots/switches off board.

I hope to use fine Kynar wire to wire the pots/switches as to make less of a rats nest, at least this is the plan in my head

[nickster]

I like the direction of Elsmurfs faceplate. However the switches end up costing nearly 90 Euros and then require having a second panel lying underneath. So I started thinking about using different switches which would mount directly onto the panel. Looking at designing a faceplate that is inspired by the MIDIMoog and this Midi controller as these designs seem to work quite well.

[Pioneers]

If anyone is interested here are the Digikey parts. So thats just about everything minus the sockets, switches and pots/knobs (I may end up changing those up a little anyway). Some parts have a slightly higher quantity because it worked out cheaper (like rounding up to 10 from 7). I've ordered mine but haven't received it yet to check for errors.

http://www.digikey.com/short/70hnn3

I noticed Mammoth has the vactrol:
http://www.mammothelectronics.com/VTL5C9-p/400-1109.htm

(EDIT: This cart has an Atmega, that should be deleted if you are purchasing the preprogrammed one. Also, the optoisolator was mistakenly added as an SMD part.)

[wahee]

had my son all day so lots of Disney shop and Marvel super heroes. So tonight its time for a bit of prep on the build. A few glasses of vino and a drill and hey presto, some cable runs for LED's switches and the like. Hey it beats the soaps on TV.

All Digikey parts now ordered, opto from Banzi and the rest from RS and eBay

Meant to say some of the builds on this post are fabulous! very well done.

Also bit of an idea for connecting Pots to headers on board.

These bare end wires
http://www.ebay.co.uk/itm/331134442188?var=540346391394

then some 6 way headers
http://uk.rs-online.com/web/p/pcb-connector-housings/7973198/

fir pretty well onto most pots and pretty secure

[sk23]

I have a issue (rev 1.1 board):
In the BoM the R181 is the 510QBK-ND but Crow wrote in the notes to use the 511XBK-ND, which one we should use?

I have only one 511XBK-ND and one 510QBK-ND according to the BoM... I hope I can use the 510QBK-ND.

Crow can you help me please?

Thank you

[colorbars]

[oldcrow]

I was just trying to save a line item. The 510Q is fine. --Crow

[sk23]

Crow I saw that now the TIS97 is deprecated, but I bought it according to a old BoM. If I want to use it which line I have to omit in the new BoM?

Thank you

[wahee]

just a bit of a general question on the pots. I have a boat load of 47 pots, can I use these instead on the 50k's. I know in UK 47K are more common and 50K maybe in the US. In most circuits I guess this is not a problem as it's so minor. Just wondered about this situation. Thanks

[oldcrow]

Except for the reverse-log pot, these are fine. --Crow

[oldcrow]

They would go where Q16 and Q17 are in the power supply area. I use 2N3904s there now after extensive testing. --Crow

[oldcrow]

Working on shipments!

[oldcrow]

First shipments of the May batch go out tomorrow. Illness and a vexing microcontroller programming issue delayed me a bit. The version of the firmware I am shipping will use MIDI channel 1 and use switch settings to select which MIDI data can affect the filter (expression pedal, key velocity or aftertouch). More later. --Crow

[ejr27233]

I just went to order a board and see you're not offering the microcontroller
at the moment. If I oreder a board now will you be offering the pre programmed chip on its own at a later date?

[oldcrow]

I need to order in more micros. The first set sold out. I will set inventory for them so they can be ordered, but I won't have them in-hand for a week. --Crow

[ejr27233]

Many thanks.
Order placed.

[wahee]

[wahee]

[Pioneers]

I was planning on programming my own chip as well. I'm assuming a sketch will be made available at some point?

So its worth noting if anyone uses my digikey cart it does have an atmega in it, that would need to be programmed or removed if you are getting one from Crow.

Also, in my cart I realized I got an SMD part for the optoisolator by mistake.

[musicismath]

That's a cracker of a synth

[oldcrow]

I'll post a sketch and a hex file for those who use non-Arduino programmers. I'll try to have that up this evening.

The SMD opto you should still be able to install, I think they leadform the pins for SMD and throughhole from the same metal on those parts.

Headed out to ship another 6 orders.

[Pioneers]

Thanks! Yeah, I think I can still use the SMD opto. I'm certainly going to try. No rush on the sketch, I'm still stuffing parts.

[oldcrow]

Not sure how but R229, a 1.2K resistor, was left off the BoM. It is there now.

[Pioneers]

I corrected the opto (from SMD to through hole) and added the 1.2k resister to my previous cart. I'm still stuffing parts so haven't gone through it all but so far the rest looks pretty good.

http://www.digikey.com/short/70vnrt

[sk23]

1% or 5%?

[wahee]

[TheInherentFloyd]

[Henfield]

Since it is going to take a while for Old Crow to offer these as a pre-assembled unit, how much would someone charge to build one of these for me? Please PM.

[colorbars]

[sk23]

Which is the part number of the opto you are talking about? thanks

[sk23]

I've another question

I would prefer my Crowminius without the leds, so I wondering if I could omit them.

Does these have a function in the circuit?

thank you

[wahee]

While I await the PCB board, I am hoping to order a minimoog panel from here:
http://www.sintetizadores.com.ar/en/news/minimoog-panel
and get started on the knobs and switches.

I have received the parts from Digikey and Mouser.

One thing I did notice was that the minimoog style rocker switches from Mouser are a little small for a replica mini panel, so I may try and get some of the larger switches. I also stupidly ordered PCB mounting pots, rather than panel mount. Hopefully I will be able to mount the PCB ones on hero board or similar and then screw that to the sub frame below the main panel.

[nickster]

[quote="wahee"]While I await the PCB board, I am hoping to order a minimoog panel from here:
http://www.sintetizadores.com.ar/en/news/minimoog-panel
and get started on the knobs and switches."

You may want to also look to get a face plate from here:

http://www.ebay.com/itm/Moog-Minimoog-Model-D-Replacement-Faceplate-/3 01114110956?pt=LH_DefaultDomain_0&hash=item461bccb3ec

if you want an original style one. But then you will need to make a plate for the extra PW options and for the jacks CV's etc.

[Pioneers]

sk23
This opto: PC900 logic output optocoupler DIP6 425-2204-5-ND

I've placed all the resistors and I noticed I purchased only 2 of the 22k when it calls for 3. Jeez. I had one laying around so not a big deal. All the other resistors looked good.

I did place both the 2.32k and the 23.2k in my cart, you can ditch one or the other based on which tempo you go with.

Also, it looks like R110 may not be highlighted in the "where's waldo" image?

[sk23]

This is my W.I.P. panel:

[medbot]

[sk23]

Crow I've an important question, that I think will be useful to others.

How we should mount the Tempco 3300ppm resistance?

I found this guide:
http://www.musicfromouterspace.com/analogsynth_new/ELECTRONIC_PARTS/Ma tched2N3904_MFTempco.php

I wondering if we should glue the transistors and the Tempco between them as described in the article?

Thank you

[sk23]

thank you Medbot, suggestions are always welcome for me

I thought I will use internal L for every part of the case, except for the upper one in which I would like to use only few wood screw.

[sk23]

Medbot, you finished the project, how do you managed with the Tempco 3300ppm resistor and the 2N3904 transistors?

[medbot]

[sk23]

thank you, can you post a picture of this?

[medbot]

[sk23]

I'm very sad :(

I didn't know that I should do this... I've already soldered all the 3046 and the tempco 3300ppm.. so I have to buy new tempco again...
I still not understand how exactly we should mount them..


The VTL5C9 need particular mount ?

thank you

[samuraipizzacat29]

How did you do it? Can you send us pictures? As long as the tempco is touching the thing that gets hot (3046?) then it is working how it's supposed to work. The thermal paste just helps to spread out the heat a little bit.

I think you'll be ok....

[sk23]

wait! I noticed that I've bought both trough hole and SMD!!

So I can remove the trough hole and use the SDM!

But I can't figure out how to mount them!

Please can you help me?

thank you

[medbot]

[oldcrow]

If you use the SMT resistors, the LM3046s mount over them. You can apply a small amount of thermal grease to the top of a resistor prior to installing the 3046 if desired. Don't use sockets for the 3046s.

Otherwise, if it is a throughhole resistor you want to bend the resistor over to the side so that it touches the top of the 3046 using a small amount of thermal grease where they touch.

Do this for each VCO.

Crow
/**/

[ElSmurf]

Am I correct in assuming that I can socket the 3046s when using the throughhole resistors? I already soldered in the sockets and want to avoid desoldering too much on the board.

[medbot]

[oldcrow]

Here is a v1.1 I am assembling for a friend. This is all the parts that use water-washable flux core solder. I take pictures now and then for illustration of assembly.

http://www.cs80.com/crowminius/Crowminius_v1.1_WashableDone.jpg

/**/

[sk23]

thank you for the picture!

I'm looking at tempcos, seems that these are not cabled and soldered to the R24,R64,R102 holes, or I'm wrong?

[oldcrow]

I am using the surface-mount ones, they are mounted inside the area for the three oscillator LM3046s. They're small, green parts near the left end of each DIP pad area. --Crow

[sk23]

Yes I know but these should not be connected or soldered in any way?
These works without to be connected?

[oldcrow]

You use either R24 or R24A, not both. Same for R64/R64A and R102/R102A. I leave the throughhole pads open in my case. --Crow

[Pioneers]

sk23, if you look closely at the board you will see the square surface mount areas under those IC's, thats what you would solder to and leave the through hole part out if you go with the SMD/SMT part. I decided to go with the through hole and now wish I had gone with the SMD, it seems like a much more elegant solution.

[sk23]

Thank you for understanding my doubt!

Now, after I've looked at the board, I understand how to solder the SMT.

[Pioneers]

Its kind of hard to tell which is the anode and which is the cathode for the LED's. Is the cathode always facing down?

[sixty_n]

they look to be all pointing cathode down but the gap in the outer circle will always be wider at the cathode indicating the flat side of the diode. At the anode the outer circle continues to the pin hole

@crow I see the boards are sold out. Are there any more coming soon?

[Henfield]

Oldcrow, besides restocking boards, do you know when you would be selling the attaché case, and a front panel for this project?

[sk23]

Crow I've bought the pre-programmed midi chip on May 12, but I didn't receive it yet!

Have you already shipped it? Do you have news about it?

thank you

[peAk]

Hi guys,

I am about to start building this and wanted to post what I am leaning towards a front panel. Does anyone notice any obvious issues?

I still need to center and align some but I just wanted some general feedback

Thanks

[medbot]

[medbot]

Here's a quick picture to give you a better idea of what I was talking about. It doesn't have the PWM section, I'll leave that headache to you

[ElSmurf]

@peAK, everything medbot mentioned. I'd expand the controllers section to accommodate the PWMs and the extra LEDs. This would give the output section some more real estate, maybe a good excuse to add the headphone out jack. And I would use a different font - most likely they used Twentieth Century for the mini, but I found Futura medium does the job as well.

The rounded rectangles remind me of my Polivoks - coincidence?

And I'm also very interested to know if and where you found those small selector knobs!

[peAk]

Oh man, all great suggestions and it was exactly what I was looking for.

Good catch about the missing stuff. The glide and decay switches were missed because when I was designing the panel, I was only looking at the minimoog panel. Totally spaced on that. I forgot about the additional stuff Crow added and I DO want to include it.

I like all your suggestions and will definitely make those changes. I still haven't quite figured out what enclosure I am using yet so that is also going to play a factor with everything. I like the Hammond style one you used but I just wish that it wasn't textured. If I could find an unfinished one that was completely angled and had a space of 17"X 10" on top, I would be all over it.

As far as the knobs, you know...I haven't tried to source them. I was just assuming I could find them which may not be the case. I have them on my Sub Phatty and really like them. I may have to look into that.

Again, thanks for all your help!

****UPDATE

Yeah, I couldn't find that size pointer knob. Maybe Moog will sell me some??? ...I guess I will redesign it with the 1-1/8" ones

[medbot]

[sk23]

Crow sorry, news about the pre programmed midi chip?

I bought one on 12 may, but not arrived yet!

[oldcrow]

I will check on it. I've had one package returned to me in the past few weeks, so it is hard to say what is happening. --Crow

[wahee]

hi Crow could you also maybe check on my order 1192 on Date 05/29/2015

I know this are busy an ll though, so just if you can


best regards

Alan

[oldcrow]

I've not shipped that week yet. Working on orders daily. I am a week behind from the flu bout. I should be into June by Friday.

[medbot]

Hey peAk - I was looking at something else and happened on this page -
http://www.hammondmfg.com/dwg21CWW.htm

It's got a 17x10 enclosure with nice wood sides and the enclosure itself looks like bare, untextured aluminum. The bottom plate isn't included in these, just a heads up there.

They've got them in black steel, too, but I wouldn't want to drill too many holes in steel (been there, it sucks).

[sk23]

ok thank you, I wrote you a PM in the forum with my name to check if the package is mine.

[colorbars]

Just placed my digikey order, can't wait to build this checking daily for the pre-programmed midi chips to be in stock again and then I'll be ready to go

[nickster]

[wahee]

[koerby]

@oldcrow

When will be the next batch of pcbs available? Unfortunately I was to slow, and now they are sold out.
What about the SMT-Variant of the PCB, can you estimate an date when it will be ready?

Marcus

[wahee]

hiya Crow, is there any special libraries for the Arduino sketch. I have the MIDI installed plus this

https://github.com/exscape/electronics/tree/master/Arduino/Libraries/D AC_MCP49xx

but getting errors on compile. I did try a direct hex upload but my board is just hanging with XLoader, still experimenting with this

thanks

[dbalatero]

[peAk]

[medbot]

[wahee]

managed to get the hex file loaded using Xloader. Seems a pretty good way to go.

Attach arduino
configure Xloader to right COM port and chip
select hex file and upload

I think the chip may have to have the boot-loader already installed?! I could well be wrong on this though as my arduino experience is basic at best

[Nargan]

Sorry but I wanted to check to see if I'm missing something obvious. I don't have my board yet so I haven't seen the BoM. I was just looking over the Digikey order graciously put together at: http://www.digikey.com/short/70vnrt

It appears to be missing things like the switches and pots. Are those being left out because there are so many part options depending on how you're going to complete your own build or am I just missing something super obvious?

[Pioneers]

Yeah, thats pretty much it. Pots and switches were left off since Those can be quite different depending on what you are building and I ended up getting mine from some other vendors (there are some items you will have to source from somewhere other than Digikey).

You can take a look at the BOM here: https://docs.google.com/spreadsheets/d/1luph-CsIEe5RU8KX1xj2FkDNPgh8RL KgIt0w2aR_KPU/edit#gid=0

You can also get to the BOM from here, and the Arduino sketch:
http://www.cs80.com/crowminius/

Also, I've built a board from that cart and everything looks good except it was missing 1 22k resistor. I've fixed that here: http://www.digikey.com/short/712030

[oldcrow]

I will restock Crowminus bare boards when the shipping backlog is smaller. I am halfway through the shipping list (this includes other boards like the CS80 filters). I estimate July 1st to be a restocking date.

I have completed the SMT rework. The SMT version will be known as the Crowminus v1.2 SMT. This will be a pre-assembled board installed in the aluminum case w/front panel only. I may offer pre-orders on the initial run of pre-assembled units provided that folks understand the earliest delivery is likely to be 90 to 120 days out. These are by no means firm numbers. There is a lot of logistics work to be done in order to ramp up production, the first of which is I need to hand-build a unit to verify it all works as expected before taking a week of days to configure my pick and place system to populate the boards. I also have to set up final assembly with an electronics shop I've used for decades for the through-hole components and case fitting. Finally, I have to devise a front panel that will work with the SMT and TH versions and that has to be debugged before production. --Crow

[koerby]

two questions:
- does the SMT-Version have the same dimesions like the through-hole board?
- Any chance to have an un-assembled pcb (I like the tiny SMT parts )

Gruß MArcus

[samuraipizzacat29]

Yeah, I'm ok with smt also. Could even help with prototyping if you want.

[oldcrow]

The board is the same size to fit in the aluminum case. (8.5" x 11" or 216mm x 280mm).

I suppose I could offer bare SMT boards as well. Some parts are still through-hole, namely the switches, pots, jacks and a few capacitors. The MCU is also left socketed to make upgrades simpler for those that don't have an ISP programmer handy.

[monkeyssj1]

[oldcrow]

I am finally up to the June orders. This coming week will see these all shipped. This includes other items like CS80 Shruthi filter boards.

I have placed five more boards and MCU chips in stock. Once these run out, the next order will be placed to arrive in mid-July.

FYI,

Crow
/**/

[sk23]

Hi Crow, sorry for trolling... I wrote you a PM on Muffwiggler about the MCU never arrived.

Please can you check your inbox?

Thank you

[gruvsyco]

Thanks for putting a few more up Crow. Just ordered, hoping my brother and I can build them in tandem. He's been building electronics stuff for years (decades), I can solder but lack any extensive experience soldering components. Pretty excited about this.

[Techman]

Progress on my Crowminius build. I've had a vinyl Minimoog front panel overlay lying around for the last 10 years. This seemed like a good opportunity to use it. Scheaffer supplied the panel. The pitch bend and mod wheel came from a basket case ESQ1. Thanks to Dimitree for the switches

The power supply has been tested. Now for my least favorite bit...The wiring

[medbot]

That panel looks fantastic, it just needs some Moog style knobs to complete the look. That's gonna be a gigantic synth

[Pioneers]

I compiled the arduino sketch. I needed a few libraries. Just in case someone else needs them here are the ones I was missing:

https://github.com/FortySevenEffects/arduino_midi_library/releases/tag  /4.2

https://github.com/adafruit/Adafruit-RGB-LCD-Shield-Library

https://github.com/exscape/electronics/tree/master/Arduino/Libraries/D AC_MCP49xx

And I noticed this important piece of code (depending on which midi library version you have):
// For MIDI 4.x backward compatibility -- uncomment next line for MIDI library 4.2 or higher.
MIDI_CREATE_DEFAULT_INSTANCE();

Also my IDE choked on these:
#include <avr/interrupts.h>
#include <pgmspace.h>

but if I changed to this it seems to find them:
#include <avr/interrupt.h>
#include <avr/pgmspace.h>

Anyone else have that issue?

[The Big Ear]

Received my board in Belgium today.
It came with a nice import tax bill of 40€

At least it arrived.
And the PCB looks great!

Cheers,

[Pioneers]

[ElSmurf]

[The Big Ear]

[Rigo]

[ElSmurf]

Looking at techman's huge and awesome front panel, I'm really tempted to stay with my first idea to make mine as close to the original as possible. Can someone tell me the exact dimensions of the original mini front panel? That might make it easier for me to figure out how to spread all the knobs...

[colorbars]

Is anyone working on a panel that will fit the pcb as it is?

[medbot]

[colorbars]

[medbot]

[oldcrow]

I am going to try and offer one. For the switches, I will be 3D-printing handle extensions, like shown below. These are small. They ideally will use a small piece of felt between the underside of the panel and the extender top to make the action smoother. I sized the height to have a close tolerance so as not to jam, but this can be changed in the 3D CAD file as needed.

The SMT version of Crowminius will use different switches.

[TheInherentFloyd]

Speaking of switches, I was wondering if it was possible to replace the default switches with these. I plan on mounting the switches to an outside cover, like medbot is doing with his.

Sorry for my inexperience

[medbot]

[TheInherentFloyd]

[captnapalm]

If you want to cut good rectangles just get a nibbling tool like this, then clean up with a fine file:

http://www.amazon.com/dp/B0002KRACO/

[ElSmurf]

[Pioneers]

I've been playing with a layout that is similar to the original but a touch cleaner and more modern. I like the the 3 rows, and the column of 5 switches and I'm thinking of consolidating all switches to get 3 columns. I've also added a section for the LFO's (PWM) and an input section at the end. I'm trying to keep the height within 3U since I'm making some breakout boards to help with the wiring and I tend to design those to fit in eurorack cases just in case in want to use them on future projects (well, and I have the free version of Eagle and its 4 inch limit). I'll probably do a laser cut/engraved acrylic panel. I tried it at 84hp, but it was too tight, this fits in 104hp. I've been looking at it for a few days and I think I'm pretty happy with it. (ignore the 3 knobs at the top, I was just swapping out different sizes.)

[wahee]

just got a rather nice metal panel from Hernán Baldi. It's very nicely done. The mouser rocker switches are too small for this panel though.

I also tried to make up a little PWM panel which may look ok with the the original mini panel. It's not great but my first attempt.

[medbot]

That big panel looks nice. For the smaller PWM panel, keep in mind that you're not actually changing the pulse width of the oscillators like your labels suggest. To do that you switch between the three different pulse settings on the waveform selector. The circuitry Crow added is just two simple triangle LFOs to modulate the pulse width, so it would be better to label the knobs as PWM and Rate, or something like that, since that's what the new stuff actually effects. Don't forget to leave room for the rate LEDs in that panel, unless you were planning to just ignore them.

I don't remember if it's somewhere in this thread or in the thread for the Eurorack sized Minimoog clone, but someone has a collection of actual Minimoog switches for sale that would work perfectly in your panel. Good luck!

[sk23]

Regarding the leds, can we ignore them? Does they have an electronic purpose in the circuit?

[wahee]

[oldcrow]

Completed and calibrated my 2nd Crowminius. This one goes to the friend who lost their model D to hurricane Katrina.

[nickster]

Nice work Crow!

I noticed you have not included the display in this build. Not having built anything with MIDI before, am I correct in assuming that the display is optional if one has a pre-programmed chip and wants to have MIDI function. Apologies if this is obvious.

[Pioneers]

Very nice! I see you used the rotary switch that mount under the panel. I've never used those before but makes a lot of sense here.

[oldcrow]

Correct, the display is optional. The firmware can tell if it is there or not without any changes.

[nickster]

Thanks Crow!

[mooman]

So from all the demos this sounds incredible. How crazy would i be to take this on as my first DIY synth project?

[medbot]

[grenert]

[mooman]

[oldcrow]

Finally, all caught up on Crowminius and Shruthi CS80 filter order shipments.

I have a few crowminius boards left before re-ordering. I will stock those on the ordering site after the weekend.

[wahee]

[sk23]

Hi,
I have a rev. 1.1 batch 1 board, and I would like to know if the two TIS97 should be stuck together with a band or something similar.

I also would like to ask Crow to check the message \ email that I sent him about the MCU.

Thank you

[medbot]

Hey Crow, could you tell me what the different settings on the MIDI DIP switch do? Thanks.

[oldcrow]

Switch #1 enables/disables CC messages that can affect filter cutoff. Switch#2 selects expression pedal or aftertouch as the mod source.

[oldcrow]

Your MCU was mailed on July 2. The transistors ideally should be touching, but they do not need to be strapped together. --Crow

[sk23]

Hello, I'm going to finish the Crowminius!

The Board is almost finished (the only left component is the pre programmed MCU) and I need to solder only the pots. Can't wait to try it!

I don't need the CV so I will panel mount only the AC and I\O jacks.

I would like to make a better front panel with serigraphs, do you have some suggestion? I didn't respect any of the original dimensions, so I wondering if there are on the net some graphics (with correct proportions) that I could adapt for my panel. Thanks

[wahee]

hi all builders. I manged to get a bit of work done on the panel.

I have the moog style switches from Mouser. They are ok, but a bit short. As I already had them , I started on making a sub plate to mount the switches on. They have a circular 10mm centre so I didn't need to cut any rectangular holes.

Some pictures so far...



more here

https://plus.google.com/photos/113787059283443546386/albums/6169253698 882969249?

[groove]

[Techman]

[wahee]

just a few quick questions.

I have 25v 1500uF caps here, can I use these instead? I'm guessing it's ok as they are for PSU smoothing

Can I substitute the pot for pitch 25k for a 10k (i'm just going to leave it centered)

[cutterfiltoff]

Such a great project! PM me if you need any panels cut on the CNC machine

[nickster]

Medbot, if I am right in assuming that you used the original sized knobs for the Crowminius I was wondering if you can let me know which pots you used as I'm trying to identify the hole diameter I need to cut for each one on the faceplate. Many thanks in advance.

[medbot]

Those panels are looking great, hope the wiring goes smoothly.

nickster- I used regular Alpha 16mm pots for everything and these switches for the VCOs - http://www.taydaelectronics.com/rotary-switch-2-pole-6-positions-alpha -sr2611f.html

[Pioneers]

That is a much better deal than the ones I got from Mouser: http://www.mouser.com/Search/ProductDetail.aspx?R=SR2612F-0206-21R0B-D 8-Nvirtualkey14860000virtualkey105-SR2612F-26-21RN

[nickster]

[medbot]

[nickster]

[wahee]

an example of a PWM extra panel i'm working on to accompany the original minimoog one. I put a modulation pot on the front as it will be a stand alone module. Pitch will just be an internal 25k pot.

Any changes / critique welcome

(now made this a bit narrower, same as controllers section on original panel)

[gwash]

I apologize if this has been answered already and I missed it, but are there shareable BOM links available? I saw in an early post that crow was intending to provide links for the BOMs on mouser and digikey, but I wasn't able to find them. I'm planning to build the board to be naked, so the default selector switches and pots are fine and wouldn't need to be swapped for panel-mounted ones.

Just got my board in the mail last week, can't wait to get this thing assembled. Thanks crow!

[nickster]

This is where I am at with the faceplate done in illustrator. Some alterations will be needed. For example I have not yet included the PWM lights or holes for mounting to the Hammond enclosure 17x10 inches. I will be using original sized knobs for the synth with smaller ones for the non original needs.

[sk23]

Hi Crow,
I'm trying to choose some pin connectors to help me to wire and solder the pots for my panel version.

http://i.ebayimg.com/00/s/NTAwWDUwMA==/z/1dcAAOxyNa9SJU-R/$(KGrHqN,!rE FIfT0lGo3BSJU-Q6vRg~~60_35.JPG

I would like to know which is the distance between the connection holes on PCB for the pots (not the 6 pole rotary) and the switches.
From website I assume that this distance is called pitch.

Thank you

[ElSmurf]

The pitch for pot connectors is standard 2.54mm, you can find these pretty much everywhere.

The pitch for the switches is 2mm by 2.5mm, which is less common AFAIK. If anyone knows where to find connectors or headers with those spacings, that would help me out a lot too!


@nickster, nice panel!

[wahee]

If you want to do it a bit ghetto you can squeeze together 2.54 header pins and they fit quite successfully.

[Techman]

It lives!!

She's ready for her debut at Synth Diy UK in Cambridge this weekend

[wahee]

Looks amazing well done

mine is nowhere near done

[sk23]

Do you have a calipers to misure the pitch of the switches?

I found a shop in Berlin that has both 2mm and 2.54 mm connectors!

[sk23]

Hello, I Would like ti buy some of these connectors (attached image) to help me to wire these pots http://cdn3.volusion.com/scund.bojht/v/vspfiles/photos/200-100-A-2.jpg  ?1398344390 but i'm in Berlin so i can't misure the width of the solder lugs. Please someone that has these Alpha pots Can check it for me? Thank you!

[Techman]

[wahee]

oh err missus - that is sexy.

that's a great job and a tidy wire up. I like the way you have a toroidal tranny in there, that's something I will hopefully get sorted.

The back panel looks great, and is nicely situated. I have a 19 inch panel QTR inch jack holes, ready to wire.

The case is very nice and gives good interior space, mine may be a bit tight as the wire looms are not as long as yours..

Did you wire the power LED directly to the LED4 PU?

I was also not too sure which way round to wire the LED's although i'm sure a look at the PDF may help

[Techman]

[wahee]

many thanks for the info on the LED's

The switch panel looks great. Labeled nicely.

I have just powered mine up, no joy i'm afraid.

Both power -+ lights on, voltage on TIP's at 10v ok

Display come up but with blocks.

A440 works ok, but no other audio on main out

headphones has a drone and a regular clicking coming from the MIDI

so trouble shooting now....

[Starspawn]

Ah the blocks, try the trim if any, it can be a looong range where its lit and still a little range only with text.

[Sandrine]

Wow! Amazing project you guys! Very nice panels. To the unknowing eye, Moog made this!

That clicking may indicate either a ground issue, or Digital/Analog ground issue. I've had that same problem before. It was because the D & A gnds were connected in the wrong place.

Also the MIDI in opto output (I'm assuming) may be shorted high?

[oldcrow]

Did you install the FETs according to the rotation indicated on the board? This is indicated for the four FETs: Q2, Q4, Q9, Q14. The VCOs wont run otherwise.

One other note: if you don't have the CV and gate jacks soldered or wired yet, you need to temporarily jumper the tip switch pad to the tip pad. Otherwise the MIDI CV/gate can't get to everything else.

--Crow

[wahee]

[wahee]

[ElSmurf]

I should get my pots and knobs in tomorrow or early next week so I can finally start working on my panel and case. You guys are making some awesome boxes here, it's really motivating!

[mikefiction]

I ordered a board a few days ago, just before they sold out

I'm excited to build this!

I think I'm going to go for close to a full sized panel with (mostly) the original placement - maybe throw the PWM stuff below the MOD section.

[wahee]

got a little bit further troubleshooting my build.

I changed the display for a Adafruit one and now get the Crowminius message and MIDI although just XXX with no midi input.

I have meticulously checked all resistors and discovered one that was wrong. A 220ohm but should have been 820ohm in the power supply. So hum is now gone.

All transistors and electrolytic caps are ok. Smaller caps still to check.

I still have no audio on the AUDIO high out.

very low audio on HEADPHONES out.
All oscillators seem to be sounding.
Although the ON and OSC VOLUME controls do very little!

so i'm thinking possible problem in mixer circuitry or VCA

[moogasm]

I trust Crow's expertise in specifying tolerances and matching but are there areas in the circuitry that might benefit from extra precision? I realize some of the inaccuracies add to the Minimoog magic but I find myself wanting to go to the extra effort of matching parts to improve performance. For instance, matching the octave switching resistors to 0.1%, the VCF ladder caps and the VCA differential pair transistors to name a few.

[wahee]

well after literally days of staring at each and every component on the board. We have success. I thought I was going mad.


Midi is still not working. Just a regular pulse on the TX light. May be the 900 opto.

I used the Gate output from a Prophet 5 (The CV out on the P5 does not seem to change pitch - probably something to do with it's spec)

So I am getting a single note. All 3 OSC's and noise are working. Noise was a it of a issue as I had fitted a multiturn trimmer and it took a hellova lotta turns.

PWM and filter also seem funtional.

Pretty amazing sounding even uncalibrated with a single note!

so feeling happy






custom panel from Schaefer AG, just a pity it's not totally matt black, plus I made the white markings too small, but looks ok once knobs on.



TIP: avoid this knob, threads strip really easily, plastic crumbles

http://www.banzaimusic.com/Synth-knob-Synthie-1.html

[Pioneers]

wahee That looks great! I built the board very quickly but have been taking my time with designing my panel. I think I just about have it though.

[mikefiction]

wahee - that panel looks really nice!

[mrcase]

Will there be another run? I deeply hope so! This looks terrific!
and Techman, whats the name of those moog switches on mouser?

Cheers
M

[Altitude909]

I still have 1 V1.1 board for sale if anyone missed out..

[wahee]

[Techman]

[oldcrow]

I am opening up an August bare board run. See the usual site, link at http://www.cs80.com/crowminius

(Look for "order here!")

Crow
/**/

[wahee]

got midi sorted out. Nothing wrong with the Crowminius, something with my controller keyboard. Perhaps its midi channel setup.

Got the Crowminius tuned up using a program from the net. Musical Tuner.

all OSC's between +- 4 %. With multiturns it would be better, but sounds fine.

working on other trims

also got my PWM panel nearly done, display to mount.

working on case

[Techman]

[Noiseconformist]

[redragebrian]

Hey Oldcrow, this is really brilliant. I'd love this but don't have the skills to build it. I'd be really interested in mounting one inside this case with a larger custom built faceplate:

http://www.thomann.de/ie/boschma_cases_mic_9_case.htm

So my question is, will you offer a fully built version of this as SMT or TH that I can then fit inside this case with the knobs and switches mounted on a separate larger panel?

Will you offer some sort of a graphics file with a pre-done layout that can be used as the basis to design a custom faceplate?

Regards

Brian

[Techman]

[mikefiction]

Got my board today! Haven't seen it yet as I'm not home

Is there a Mouser cart? I've looked through the tread a couple times and I failed to spot one?

If not, no big deal, I can make my own - just would be much faster and probably more accurate

[oldcrow]

My Crowminius SMT v1.2 (version bump for SMT) bare boards are here. I will hand-build the first one to verify everything works then it is off to my SMT shop to spend a week setting up the machines to build the SMT portion.
There are still some through-hole components: mostly pots, switches, jacks and a couple parts that need to be mounted with heatsinks, etc.

More later,

Crow
/**/

[moogasm]

Are there areas in the circuitry that might benefit from extra precision? I realize some of the inaccuracies add to the Minimoog magic but I find myself wanting to go to the extra effort of matching parts to improve performance. For instance, matching the octave switching resistors to 0.1%, the VCF ladder caps and the VCA differential pair transistors to name a few.

[groove]

[redragebrian]

Thanks for the reply Oldcrow. If you're taking names, can you put me down for a pre-built SMT model?

Will this have the pre-programmed midi module chip installed?

Thank you!

Brian

[Noiseconformist]

Speaking of Feedback ...
Anyone normalised the (an) output to the external input?

[sk23]

Hi Crow,
I would like to have some info about the midi implementation (no CV) with the your pre programmed MCU.
1) Does the velocity MIDI control affect the VCF?
2) Does the pitch bend MIDI control affects all 3 VCOs?
3) When 2 MIDI notes are overlapped does this generates a slide between the 2 notes? (not a fixed glide)

Thank you!

[redragebrian]

Sorry Oldcrow, another question.

Would a TH version be better in terms of future repairs by my very capable synth tech?

I'm trying to avoid having to hire someone to build the synth from scratch, hence my interest in the SMT version. But I don't want to end up with a synth that requires specialist SMT repair tools.

[Techman]

[Noiseconformist]

[oldcrow]

Currently the two DIP switches select MIDI->VCF modes. When you set DIP switches 1 and 2 both ON, the key velocity will output a voltage on the second DAC channel which can be scaled with R20 "VCFCV level."

Setting sw1 ON and s2 OFF will select the expression pedal (MIDI controller #11) for VCF brightness, and setting sw1 OFF (sw2 won't matter if sw1 is off) will use the aftertouch/channel pressure to control the VCF.

Eventually I will actually document this.

There currently is no MIDI pitchbend, although I will implement that once I get through the ramp-up of the SMT Crowminius. When implemented it will affect all oscillators.

The note rollover is last-note priority to allow legato/trilling, which means the note does not retrigger unless all keys are released.

Crow
/**/

[oldcrow]

My SMT version should be easily repairable by any competent tech should it ever need repair. I do not use super-tiny parts for synthesizers. SMT rework is ten times easier for things like resistors, caps, etc. anyway.

Crow
/**/

[redragebrian]

Thanks Oldcrow, that sounds great. If there's a waiting list, put me on it. Otherwise I'll assume you'll post here when they become available to buy.

[sk23]

Thank you for the infos.

Correct me if I'm wrong, I assume that the MIDI pitch bend will be implemented as a Crowminius MIDICV update for the ATMega chip.

I will check regularly your page http://www.cs80.com/crowminius/

Thank you

[wahee]

got my Crowminius tunes across 3 oscillators. All 2 play in tune. Using the attech portion of the Minimoog service manual (although the pots seem to be reversed)

I have an issue when I switch range from 2' to say 4' OSC2 & 3 are no longer in tune and I have to adjust frequency to match. IS this normal. I have no experience with a Mini so maybe this is.

I have adjusted the range pots, but these seem to throw out the entire tune range.

Also what do the COMP trims do. Are they compensation?

Had a look at the mini service manual but not clear about these

Thanks

[The Big Ear]

I've finished mine yesterday and after some trim tweaking got all pots and switches to do what they are supposed to do.

Today I continued to trim it further and noticed a couple of issues on the power supply.
I use a 2x12V AC torroid transformer. Transformer gives 12V on red/yellow and Green/blue. I connected blue on J17, green and yellow on J18 and Red on J19.
Power leds are on, but phase led is not working.
I measure +7,6V trimming the trimpot does not change anything. On the pins of the TIP32C I have 17v/7,6V/17V
I measure -8,3V to 6,6V, so this trim works a bit. On the pins of TIP31C I have -18V/-8,3V/-18V.

Did I connect the transformer correctly? ANy other things I should look at?

Thanks in advance!

[oldcrow]

This sounds like an incorrect part value somewhere. +-17V on the pass transistors is good, double-check parts values for D15, R259, R260, R264,
R266 and trimmer R265. If the phase LED is off try the alternate setting of the "phase" jumper block JP1. Also, you can pull both jumpers and
check if it is operating correctly in half-wave mode. --Crow

[latigid on]

Sent a PM to Crow but perhaps he didn't get it?

Off topic: what's the best way to ship PCBs of this size? Flat or in a box with padding/polystyrene foam? I will have some of a similar size to ship soon. Just a description or a photo of the box would be very welcome.


Many thanks,

[sk23]

Hi guys,
I've just finished my crowminius but no sound is emitted!!

I didn't mount the leds, but even the test tone 440 is working.

I tried with only one wall wart connected to J6, changed the phase jumpers (and even removed both) nothing is changed..

I'm disperate! After 3 months of hard work!

I'm not good in troubleshooting, any help is highly appreciated!

Thank you

[The Big Ear]

Thanks Crow, I checked the PSU area again and found a bad solder joint. Solved it, now I have a steady +/-10V.
Still, whatever I do I can't get the phase led to light up. So I removed the jumpers and will keep it this way.

I need to check some mod's I did (keyboard to VCF switches replaced by a pot, VCA CV in through a pot, VCF CV in through a pot & SW8 used 2 switches instead of one) but it already making sweet sounds so looking forwards to when I get it 100% ready!!!

Cheers,
ToAd

[sk23]

Hi,
got the crowminius emit some "sounds".

The test tone 440 is working but, I don't know if it's normal, pots and switch doesn't affect it.

But when i play some notes via midi (din) I hear some clicks only, no notes or anything that the tune\octave pots affect.

Low output is not working, hi output is quiet and headphones out seems to work well.

There was a terrible hum with one wall wart, but when I use two of them it disappear.

Any help is appreciated! Thank you

[oldcrow]

The A440 tone goes straight to the final VCA, so nothing will affect it aside from volume.

Check to make sure all four FETs are installed at the indicated angle, one per osc. and one for the OSC3 mode CV switch:



Crow
/**/

[sk23]

Hi Crow, thank you for the reply.

Yes the FETs are in the correct position, but i noticed that I used 25 ohm trimpot for R185, R265, R273 instead of 100 ohm as wrote in the notes.
Same story for R233 I used 2.5K ohm trimpot instead of 5K ohm as wrote in the notes.

Does these different values can cause the problem?

If not, do you have other suggestions for what to check?

thank you

[wahee]

make sure ALL the jacks are fitted correctly, especially if you are wiring off board. I had made a mistake on the loudness jack which stopped any OSC output. If in doubt wire the PCB jacks from the original BOM. That's what I did to check if the problem was my off board wiring, which it was

[sk23]

thank you for your help.

I used and I have already soldered all the original 1/4 PCB mount jacks from the BoM
http://www.mouser.it/ProductDetail/Neutrik/NMJ4HFD2/?qs=eq47NuTtZvktEC FTcsfPAA%3d%3d&_cdc=0

but I didn't buy The vertical jacks because i don't need cv:
http://www.thonk.co.uk/shop/pj301bm-3-5mm-jack-sockets-x50/
Does this could be a problem?

As I wrote in my previous post, the trimpot with different value could be a problem?

thank you

[wahee]

hi

[sk23]

Thank you Wahee for the input!

Crow please can you confirm that is needed? There is a workaround I could do without buying the 3.5mm Jack Sockets from Thonk?

Thank you

[The Big Ear]

[oldcrow]

Two of the jacks need their tip and tip-switch pads (T, TS) jumpered as they complete a circuit even if the jack does not have a cable plugged in. This means you install a jumper from the top pad to the bottom one for J2, and from the left pad to the right pad for J3.

No jumper is need for J1 or J15.

Crow
/**/

[sk23]

thank you very much Crow! now everything is clear!

[sk23]

I did the jumper connection but the issue is still here

The midi input is working but the synth emit only a click when a note is played.

Low output is still not working.
I've checked with beep all the FETs pin S G D that are correctly connected to the capacitors, trimpot etc
All the 6.3 jack socket that are correctly connected and soldered.

I think that I should bring it to a synth tech repairer

Any other input is really appreciated.

thank you

[The Big Ear]

[sk23]

guys got it working!!!! the sound is amazing!

the problem was that I soldered the switch's pins only on the upper side of the pcb board and probably there was a lack of connection.

Now remain only the calibration.

Thank you Crow for this amazing project and for your kind help

[Techman]

[oldcrow]

Working on a front panel while waiting for the SMT parts to arrive. This is the v1.2 (SMT) panel which is slightly different. I will make a v1.1 panel once I verify this one fits. It is contoured to fit around the 1/4" jacks and in order to save on panel price, it does not cover the entire board.

[wahee]

hi Crow that panel looks great, love the logo, I think I will order another board once I finish this one completely.

Have you any advice to get the range tuned better. I have the oscillators all in tune as per the Minimoog service manual using the 2' range. But when I drop to 4' or 8' the scale does not drop a full octave down. I have to readjust OSC2&3. Adjusting the RANGE pot throws the entire oscillator tuning off.

It's not a huge deal as I an just adjust OSC2&3 frequency controls a bit to compensate, but would be nice to fix if at all possible.

s it also possible to increase the noise gain as on my build it's quite low compared to the oscillators. I have not tried to tweak the VCA balance as I got a bit confused with the Minimoog manual - connect point A to point A malarkey

[sk23]

I have the same issue.. honestly I can't either get the scale A to A to the upper octave.
A guide would be really useful.

I use midi din input, and I have 121k 1% for R4 and R6.

[sk23]

Guys I discovered that if I tune the synth to the high A and I switch down the octave using the octave switch the tune keep perfectly, but if I play on the midi keyboards the A at a lower octave the tune is loosed (it play a C note).

So I suppose that is something wrong with the cv \ midi section.

Assuming that I want to use the synth only via midi din, maybe I should use 100k for for R6 and 102k for R4?

Thank you

[medbot]

Have you guys done the octave calibration? That's a separate thing from the initial note-to-note calibration. You need to do both. I used a combination of the service manual and this text file I copied from somewhere to calibrate mine. It's been a while since I did it so I don't remember all the specifics, so you're on your own there, but these documents and a few comments from Crow in this thread will be everything you need to get it calibrated. I think you use the calibration notes for the third VCO type. You might also want to grab a free software frequency counter if you don't have a good tuner. Good luck!

[sk23]

Thank you Medbot for the manuals.

I did both indeed the tune is kept if I scroll between octaves with the octave selector.

The problem appear when I use the midi input (no CV).
I suppose that the problem is the value of R4 and R6 resistors, at the moment they are both 121k.

If I want to use Crowminius via midi which between 1v/oct and 0.815v/oct is the correct configuration?

Thank you

[medbot]

The MIDI input does not bypass the CV, it gets mixed in with the external CVs before going into the exponential converter, which is what you're calibrating. You would most likely have the same tuning issues using a CV controlled keyboard with no MIDI, unless there is something wrong with the chip or your controller somehow. I wouldn't go changing resistor values arbitrarily unless I knew what I was doing (which I don't, in this instance). Do you have any experience calibrating VCOs before? It took me a while the first time I did it, and it sounds like you just haven't quite gotten yours zeroed in yet.

[sk23]

thank you for the reply.

This is my first time in calibration, but on monday I went to a technician that projects and builds euro modules, he is 50 years old and has a lot of experience in tuning new and vintage synths.
He didn't menage to tune the crowminius across the midi keyboard.
In my opinion the fact that the synth keep the tuning when the octave is changed by the octave switch selector is an important indicator, you agree?

Today I read this note for R4 on the BoM

For 1V/Oct operation from external CV, change to 121K. 102K is for 0.815V/Oct using onboard DAC

I though if this 0.185v difference could be the reason for the variation of few semitones between A and A at the upper o lower octave when played with the midi keyboard.

This is possible?

Thank you

PS: My build has the pre programmed MCU offered by Crow.

[Altitude909]

So is the panel designed to fit the PCB with all controls PCB mounted?

[oldcrow]

This particular panel is. I can make a rectangular version that can be used off-board, however. I mainly wanted a panel for the briefcase for now.

[oldcrow]

To use the MIDI MCU make sure R4 is 102K. If you are going to use the external CV/gate for 1V/oct keying make sure R4 is 121K. The onboard DAC uses an internal 4.096V reference, so in order to get 5 octaves of range I scaled the key CV response to 0.815v/oct. External CVs are not constrained to this 4.096V reference and so the more common 1V/oct. can be applied.

Crow
/**/

[wahee]

thanks medbot. I'm using 102K resistors and midi.

on the txt file there's

SHIFT
SCALE
HI-END
RANGE

on the Crowminius;

ZERO
SCALE
OCT
COMP

apart from scale, can you recall which matches with which

thanks

[oldcrow]

SHIFT = ZERO
HI-END = COMP
RANGE = OCT

[wahee]

[sk23]

Hi,
did you check if the OSC 3 control is on? I read on the calibration manual that should be on during the calibration.

Hope this help

[tuttlerecall]

I am working on a rev 1.1 first round board. Is there a socket I can use on the board for the ATMEGA chip in case I want to try to update the firmware on it in the future without having to de-solder it?

Should all of the ICs except the LM3046 (with smt underneath) be socketed? Will the rest of the ICs make it without sockets?

Crow- You referenced earlier being at a point on a 1.1 board that you were done with all the components that use flux core solder. What do you use for the rest of the components?

Also it looks like currently there is no way to do both 1v/oct external CV and 0.815V/Oct using onboard DAC without re-soldering R4 and R6?

[oldcrow]

You can use any 300mil 28pin IC socket ("skinny DIP") such as
http://www.digikey.com/product-detail/en/ED281DT/ED3050-5-ND/4147600

You can socket all of the chips if you want. The VCO 3046s gain a small advantage in not being socketed but most of the temperature equalization between the 3046 and the tempco is made through the circuit trace, given the tiny thermal mass of the tempco.

I use water-washable solder aka Kester "331" (Kester part no. 24-6337-6401) for all hermetically-sealed parts. This means resistors, transistors, ICs and some capacitors.

I use a low-residue flux solder such as Kester no. 24-6337-8800 for things like pots, switches, aluminum caps, headers and jacks.

For external CV control you only need to worry about R4. In a future rev. I might add a jumper option for this.

--Crow
/**/

[evengravy]

Sorry to stray off topic but have you looked at the teensy for USB midi. I've just did a major project with it and it is the business. The boards are more expensive vs arduino but worth looking at. I've just ordered from the August buy so might even have a crack at it. Doing it with an arduino isn't that simple unless the ftdi chip is replaced, the Leonardo can do it but otherwise I'd look elsewhere.

[TheInherentFloyd]

Quick question, 'cause I'm a little confused. Should the 2.32K resistors on Rev 1.1.2 (R23, R63, R101A) be used the with the SMT 3300ppm resistors or the their through-hole alternatives? Sorry, the BOM is worded strangely to me.

[oldcrow]

There are two things to note here.

1) If you use 2.32K, the tempco should be 100 ohms. If you use 23.2K, the tempco should be 1K ohms.

2) the type of tempco resistor can be either SMT or through-hole in either case of the above.

I provide a choice for these values and packages because some parts are easier to obtain than others, and some parts people already have on hand from other projects/repairs.

--Crow
/**/

[TheInherentFloyd]

[wahee]

[oldcrow]

Got the panel today. Aside from having to correct one hole the wrong size it all lines up perfectly. I need a few more 12mm brass screws for the front edge, and the actual production Crowminius will use PKES60 1/4 knobs for octave and waveform selectors (not the PKES90s shown), but otherwise this is how I originally envisioned the project.

[mOBiTh]

[mrcase]

Hey crow!

Thanks for this amazing project. I´ve preordered a board last week and was wondering if I could buy a preprogrammed chip with it. Will you have them back in stock and is it possible to add one to my existing order? It will be shipped to europe.

thanks and cheers
Martin

[oldcrow]

It isn't going to get much more compact than this. I have had requests to make the filter+VCA as a eurorack module, so that might happen once I sell enough pre-assembled Crowminius units to fund it, but I have to get back to getting the crowbx euro module production-ready.

[ElSmurf]

I received my acrylic underpanel from Formulor a few weeks ago, but it arrived two days before leaving on holidays, so I couldn't get round to assembling it until yesterday. Here's a crappy picture :


It's almost the same width as the original (thanks wahee for the correct measurements) but I added a sixth row at the bottom for the PWMs and put the VCA section on the row below. I also added the modulation knob in the controller section. Next step is starting the woodwork for the case, and then to get everything wired up. This is such a great project!

[tvh]

I also placed an order yesterday and can't wait for the next batch! Really excited to build this

[oldcrow]

FYI, my board orders seem to suffer a week delay now that the supplier has a US office. They must bulk ship to the US office from Shenzen and do all the order shipping from there. More Crowminius boards are on the way, just later than I intended.

[mOBiTh]

[oldcrow]

I am going to go ahead and list pre-order inventory for assembled units. The production prototype is complete, and after Knobcon I will be getting board assembly line going.

[sk23]

This is great!!!

The option 3 will be even without potentiometers? It will cost less than 699$?

Thank you

[oldcrow]

The 2nd option will be $599. The case, panel and knob set cost to me is just under $100 which is why I set the 1st option price at $699.

The 3rd option I do not quite know the expected price yet. It will not have pots, switches, jacks or LEDs to allow the builder to use their own case and panel mountings. I need to devise a test platform for that option so I can still calibrate the unit.

--Crow
/**/

[sk23]

Ok thank you for the infos!

[colorbars]

Holy crap... Just now realized that there's links to pics of the board with each part highlighted in the BOM Things will go a lot faster now

[jhulk]

scott the 8 voice midi to cv you created for the crowbx 8voice will you be doing that as a kit

as waiting for the crow minus board im designing a 5 octave keyboard as i have a few spare fatar keybeds and going to be making a boat for all the controls and want to fit 6 gang alpha pots and elna 6 gang switches for a possible poly version

i had a memorymoog and it was a fat synth but not a poly minimoog apart from the moog ladder filter its mostly cem chips for sound and modulation

the pcbs will be housed in the bottom casing of the keyboard and flying leads to the boat for the pots and switches

i have a krautrock phaser already populated for it and moog 914 filter bank

what is the impedance output of the crowminus as i want to fit a balancing isolation transformer from sowter like was fitted to my memorymoog

thnaks

[oldcrow]

Order update has the latest batch of boards now traceable (shipping). Hope they do not languish a week in California.

[sk23]

Hi,

I feel really unlucky with my Crowminius

A short circuit occurred in which Q3 and T3 have burned.
Now I have replaced them.

Anyway I feel that something is going wrong, because to have a stable tune I have to wait 20 minutes.
Before that, the tune was stable almost immediately.

Do you think that 20 minutes is a normal time for the circuit to become stable?

Could be possible that something else were damaged? And in the case what?

Thank you for your help

[tuttlerecall]

Thank you for the recommendation for sockets and solder. My board is looking much cleaner.

Are you still planning on doing a v1.1 panel that would fit first run boards?

Do I need longer pots if I want to do a panel later? Should I also use 2mm socket headers on the switches and the overload LED? Are there different switches altogether I should use? Most of my pots are the 9mm. Do I need different rotary pots as well?

[colorbars]

While clipping off leads I accidently nicked a trace (between r124, r129 and a 2n3904) . There's still continuity but it's not reliable. Is there anything I can do short of soldering a wire between the components in place of the trace? And if I do this is it safe to leave the old nicked trace?

[oldcrow]

If you did not entirely cut through the trace it should be fine. Otherwise use a short bit of insulated wire to make the same connection using resistor leads as the endpoints. --Crow

[mOBiTh]

a simple reinforcement with solder ought to fix that trace if there's bare metal showing either side of the nick...

[Fiflouc]

Hello, Is it possible to use CA3046 instead of LM3046N? it is easier to source.
Thanks!

[Altitude909]

[jhulk]

get a fiber glass erasure and remove the solder mask either side of the cut and solder a lead from a cap across the cut smd style soldering just flood with flux and solder it will only flow on the lead and solder tracks

or add a flying lead from the pads that the track joins

[colorbars]

Thanks!

[phutureboy]

[oldcrow]

The latest board batch has arrived. I will start posting orders.

--Crow
/**/

[samuraipizzacat29]

Have you posted files or made panel files available for sale? I was going to go off-board, but then I found this little case I had tucked away that will be PERFECT for this. Your panel design and hole locations would help immensely for when that day comes.

[Fiflouc]

[TheInherentFloyd]

Would it be possible to set up a switch to toggle CV and MIDI? Could I simply set up a switch between resistors connected to R4 or is there more to it? Also, with R6, is it 121K no matter what or only if you use CV?

[oldcrow]

To select the scale you would want to change R4 between 100K or 121K (or 102K, but I'm using 100K without problems off the DAC). For 0.815v/oct or 1v/oct.

The main issue is you have to calibrate it for either one using the trimmers. I suppose you could place a small 50K multi-turn trimmer in series with a 100K 1% resistor and have the switch short out the trimmer portion for the onboard DAC mode, and enable the trimmer for 1v/oct mode. Then (using this trimmer) you do not have to recalibrate the oscillators for 1v/oct scaling.

If Microchip DACs would use an internal precision 2.500v reference and not a 2.00v one this issue would not even exist. The reason for this is because they don't want the 2x gain mode of the DAC (which I use) to result in a reference voltage that is higher than the supply voltage. Thus all this 2v/4v stuff.

--Crow
/**/

[wahee]

I finally have my Crowminius working fully.

Took 4 weeks to find the issue.

Osc 1& 2 tuned in 10 mins, but OSc 3 was always 40% off.

After lots of head scratching I replaced all the IC's as all resistors were ok. Turned out TL072 was suspect. It was brand new so I was very surprised.

Replaced with gold turned IC socket and new chip, so all is good and 3 OSc's all rock!

(used it on a new track for bass, it's great for think lines)
https://www.youtube.com/watch?v=XS7HEl8q_N4

[Fiflouc]

Hello,

As adafruit LCD is out of stock, I found this one : https://www.sparkfun.com/products/13293 , I can see there is no IC. do you think it will work?

Thanks!

[evengravy]

Any news on the rough shipment date of the August bare board run if you don't mind me asking crow?

[Techman]

[oldcrow]

I started shipping last week. More this week.

[colorbars]

Are you going to do a run of the 1.1 panels? If so I'm definitely down for one

[oldcrow]

yes, this will be after Knobcon. This whole week I am swamped getting ready for it.

[evengravy]

[Pioneers]

I'm having a few issues now. I stuffed the parts quite a while ago and have spent some time designing my panel and building a case. I then went to wiring up all the pots and switches so it wasn't until this weekend that I powered it up for the first time. There was no audio, except for the A440 tone. I went over my solder joints and found a couple of questionable ones and found a damaged trace on the board. Once I fixed those I now have some audio, mainly OSC3 seems to work somewhat well. OSC2 only has some seemingly random tone and I get nothing from OSC1. The filter seems to work, as well as the glide. I'm not certain the "Loudness Contour" is doing anything. OSC3 mod LED will not light. I've checked the power supply and get +/-10 volts and get 5volts over by the atmega. The midi seems to work, I've been testing with a midi controller and the gate LED lights and I see the TX light change brightness. The PWM LFO's seem to work. I'm wondering if I damaged a chip or transistor now, and I'm continuing to look over all the parts. It's gotten much more difficult now that I have all this wiring in place. The bits of noise I'm getting from OSC3 sounds pretty great at times so I'm getting excited but there must be something else that I've messed up.

[oldcrow]

More board orders shipping this week, sent a few off today. About halfway through the order list. Still recovering from Knobcon.

[oldcrow]

I will mull over possible things to check. That one osc appears to track means the front-end pitch voltage summing circuit is working. More later.

[tuttlerecall]

I just "finished" my board but so far can't get a sound out of it. Only one of the power supply LED's lights up when its turned on and the A440 note doesn't work either. Tried all jacks. Any ideas where I should start?

[Pioneers]

[vilmycil]

Hi guys,

First time poster, long time reader. Some smaller diy projects under the belt.

I am finishing off my build. I've powered it on and I can see the led's on (power, lfo, midi). I use only one psu (no phase light I assume is ok?). Test tone works, but there's only a very very weak sound that reacts to frequency,range, lfo changes and midi input. There's an odd click when a key is pressed. I hope it's only due to lack of 3mm CV jacks.

I am about to do them. But I can't figure it out where's tip/ring on the board on EXT VCF CV, EXT PITCH CV, EXT LOUD, EXT STRIG. (noob)
Anyone?

Thanks a lot!

[Pioneers]

[tvh]

Just started populating the boards last night, this is the densest board I ever attempted! Thank you Crow for the pictures of each component placement

I'd like to go the front panel route - how are you guys wiring the controls to the board? I saw some pics earlier in this thread that looked like headers? Could someone clarify how they got headers to fit on the board, did you take a 2rowx6position and just clip the leads to fit into the pot mounts, for example?

OR, did anyone just wire panel controls direct to board? I am not sure of advantages/disadvantages either way in this case since there would be so many headers instead of 2 or 3 monster ones as in traditional panel PCBs.

Is 26 gauge ok for board to panel controls? I have some ribbon cable already in that size and would help keep it tidy.

Everyone's progress is amazing!

[vilmycil]

Hi all,

I've got it all wired up. And as much as I was very careful and patient - I've got issues.

It switches on, one 1000mA PSU, no phase light, PW rate led's respond and work, midi and tx respond to midi messages, tune tone is working etc.

But trying to play it, I get a click per each key stroke, noise and only vague and very weak sound of oscillators that respond to frequency change, range etc. I can hear changes to loudness contour. But nothing happens when I try changing filter settings.

Also, aftertouch results into a digital noise. You can hear it on the recording I made.

Here's a recording of what I hear... ( http://tinyurl.com/o4dlmto ) Any tips? I've checked all soldering joints and I do get 5v at atmega.
Pretty much all of the parts are exactly the same as on the bom apart from a few capacitors, tempco (farnell p.no. 1174306) and CA3046...

Would appreciate any advice.
Thanks all!

[vilmycil]

Do we have access to the schematics of crowminius? I don't know how, yet. But I hope to figure out what the heck isn't working...

Any help and advice is very welcome.

Thanks

[oldcrow]

The schematic and board reference is here:

http://www.cs80.com/crowminius/schempdf/

From the description, the filter has something wrong. Double-check all the values and polarities there for starters.

Crow
/**/

[vilmycil]

I will double-check. Thanks Oldcrow.

Just a quick update. I've been checking voltages coming from IC's.
I'm not sure if this is at all helpful, but here's what I've got

LM348 Vcc 9.43 -9.10
TL072IP Vcc 9.46 -9.13
LM1458n Vcc 9.47 -9.14
PC900V Vcc 4.96
Notably
MCP4822 Vdd 4.96 with nothing at Vss... Should there be anything?
Thanks

[oldcrow]

Sounds like you need to trim the power supply for +10.00v/-10.00v.

Use trimmer R265 "P10V TRIM" in the power supply corner to set the positive rail (measure from an op-amp to common) to +10.00v, then use trimmer R273 "N10V TRIM" to set the negative rail to -10.00v.

Also make sure the filter range trim R148 and scale trim R158 are near their center positions.

[Pioneers]

I've replaced all my IC's and it functions the same. I've continued to look at traces and haven't found anything. I thought I was very careful about part placement but now I guess the only other thing is to start rechecking a misplaced part.

[Kfinch3420]

First I want to say thank you old crow! You are what I aspire to be! ..I was an ee in training in Milwaukee, Not far from chi, before having to take sometime off to work .Hopefully once I finally finish, I can be as big an asset to the synth community as you are

Anywho, I was wondering when/if there will be any more bare boards for sale in the near future? I know you're hard at work on the assembled units, maybe you have a spare board?

Peace,
K

[sixty_n]

@kfinch they come back in stock every month or thereabouts so you shouldn't have too long to wait

[vilmycil]

I have adjusted voltages to ±10V as per Oldcrow. I seem getting power coming through all the IC's. I ran out of ideas what to check. All components seem to be oriented correctly.

I have included a link to some pictures for visual reference. Perhaps those that are good at it, could spot something I missed?

Also I noticed osc volume doesn't really bring any changes to whatever weak and noisy sound I'm getting at the moment.

For those that still building, I would say - use ic sockets. I wish I had. Wiring of board also makes troubleshooting much more difficult! Just a thought..

Pictures: https://goo.gl/photos/D5gYTh9sc9k5B2oz9

I am eager to learn, and would appreciate any advice how to approach this troubleshoot.

Thanks!

[Pioneers]

[Dune357]

Just Got my dispatch notice today Thanks Old Crow!

How difficult would it be to build this with a Keyboard attached rather than a rack unit?

Thanks.

[tvh]

Crow would it be possible to post a hi-res PDF of the 1.1.2 layout? The one you have up is 1.1 and I can't match up some components. I'm a little lost at the glide lock area, there seems to be a few spaces for capacitors that aren't on the BOM or the PDF. For instance, I can't find C120 on the list or there appears to be a cap perpendicular to C119 and next to IC25.

Also I need the 1.1.2 layout hi res because I have an extra 100K but after hours staring just can't find it on the board.

[sk23]

I saw you didn't use the minijack sockets like I did.
So try to do this, it has resolved my similiar issue:

Two of the jacks need their tip and tip-switch pads (T, TS) jumpered as they complete a circuit even if the jack does not have a cable plugged in. This means you install a jumper from the top pad to the bottom one for J2, and from the left pad to the right pad for J3.

No jumper is need for J1 or J15.

Crow
/**/

[oldcrow]

Here is a hi-res image of most of the discrete components. This is a 2448 x 3264 pixel image. I do not have a TH version here with parts installed to show the glide lock, but C120 and C121 are bypass capacitors (0.1uF).

I will update the BoM page.

Is the extra 100K the emphasis pot taper option R145? If so you do not need it if the pot is a C50K (reverse-log type).

Crow
/**/

Crowminius 1.1.x discrete parts

[vilmycil]

Thanks. I have used switched sockets, so tip and switch are connected when nothing is plugged.

Interestingly, I had exactly same same output/result before I did them. Perhaps this is a clue pointing towards the area of issue?

I would like to avoid swapping the IC's unless it's necessary. Is there a way to find out? Or should I invest time into getting them out and swap into sockets and new parts?

Thank you all

[jhulk]

dont swap ic scope it a scope is your best friend it will save you time and money with faults easy to put clip on ic pins and look to see whats going on

[tvh]

Thanks for the reply. I'll keep at it and come back if I hit more snags (which I'm sure I will )

[oldcrow]

Heya folks,

I have shipped all of the Crowminius boards from the September batch and will be ordering one more board set this year. I expect to start shipping those in mid-November. For those interested, order info is at the usual link from http://www.cs80.com/crowminius

Otherwise the next batch will be sometime in Q1 of 2016.

Cheers,

Crow
/**/

[captnapalm]

Hopefully it's helpful to someone: the polarity on all the LEDs is positive up (+ towards the "Crowminius" text on the PCB).

[colorbars]

Any news on the 1.1 panel, crow?

[captnapalm]

Anyone have a recommended wallwart that has the appropriate jack already (US)?

[Pioneers]

[captnapalm]

[peAk]

Hey Crow,

For some reason, the linked png files on the BOM aren't fully loading today. I have tried on two different networks to make sure it wasn't anything on my end. I have never had trouble before today.

Thanks


*****working now

[tonyg59]

Just received my dispatch notice from Old Crow today (Thanks).

Looking forward to building this over the coming months.

Let the part ordering commence....

[captnapalm]

Has anyone tried to compile the FW via Arduino? I was hoping to program it via Mac and avoid dusting off my old PC.
I got the following declaration error:

Crowminius_MIDICV_v2_release.ino: In Function 'void setup()':
Crowminius_MIDICV_v2_release:232: error: 'MIDI' was not declared in this scope
Crowminius_MIDICV_v2_release.ino: In Function 'void loop()':
Crowminius_MIDICV_v2_release:253: error: 'MIDI' was not declared in this scope

[Pioneers]

[captnapalm]

[Techman]

[captnapalm]

[qp]

I must know, to those that have finished building this, how in the hell did you keep your eyes from popping out of their sockets?!? I'm 8 resistors in and my eyes are already killing me! There's just way to much going on on the board to make any of it out. I was thinking of going through on a jpeg and whiting out all of the designations and values and replacing them with larger designations, but that just way to much time of which I don't have. Does anyone have a simpler PDF of the PCB with just the designations?

[spneca]

[qp]

[captnapalm]

[captnapalm]

Seems like I have varying voltages coming out of the DAC. Will keep tracing.

In poking around I found 2 caps that aren't on the BOM so I hadn't stuffed them:

C120
C121 (I think, hard to read)
both marked 104

They're near the glide lock components so I assume they have to do with that circuit, but thought I'd mention it so they can get added. I added them but it didn't solve my issue.

[colorbars]

Might be a silly question but I put a 121K resistor for R6 for 1v/oct as the BOM noted it was changed to this for 1v/oct external cv but I notice for R4 (102k) there's a option for changing R4 to 121K for 1v/oct external cv as well. Does changing R4 to 121k make J13 (1/4" cv in) 1v/oct? Otherwise it's just J1 (1/8" cv pitch) that's 1v/oct? Just a little confused as to if/why I should change this one to 121k

[wahee]

trying to compile MIDICV_V" but getting a ton of errors...

X:\my documents\Arduino\libraries\DAC_MCP49xx/DAC_MCP49xx.h:13: error: stray '\302' in program
X:\my documents\Arduino\libraries\DAC_MCP49xx/DAC_MCP49xx.h:13: error: stray '\267' in program
X:\my documents\Arduino\libraries\DAC_MCP49xx/DAC_MCP49xx.h:13: error: stray '\302' in program
X:\my documents\Arduino\libraries\DAC_MCP49xx/DAC_MCP49xx.h:13: error: stray '\267' in program


I have all the libraries it seems

?anything I missed

arduino IDE 1.06

[mcbinc]

[wahee]

hi thanks for that. I will remove the program and retry

latest update on Crowminius build

[Techman]

Coming along nicely, Wahee

[captnapalm]

Has anybody built a Rev. 1.1.2 board and not added the "optional" glide lock components?

I'm getting CV at IC21 pin 1 but it's not making it to IC1 pin 2.

From what I can tell, pin 1 of IC21A only has one trace, and it goes directly to R386 which is part of the glide lock circuit. So I can't see any way for the CV to get to the oscs.

[oldcrow]

If you are not installing glide lock option you have to install a wire jumper (or something like a 10-ohm resistor) from IC25 pin 3 to IC25 pin 5. There is a dashed line on the silkscreen to show this. I think I noted this in the BoM, I will verify. --Crow

/**/

[captnapalm]

[wahee]

[qp]

[peAk]

Can someone recommend a friction header/housing that fits the (2X3P) switch connections? I want to order some but I am not 100% on which ones fit. I know they have 2mm spacing but I am concerned about the row spacing.

Any help would be greatly appreciated!

[partycentral]

[wahee]

[qp]

[wahee]

[qp]

[colorbars]

For those that are using pots directly mounted to the pcb... what's everyone doing for the pitchwheel and modwheel pots? All the photos I've seen from crow show one vertical and one right angle pot (shaft pointing away from the board). On the board itself it shows two right angle pots with the shafts facing towards each other?? What's the best way to go?

[wahee]

Crowminus is finished. The case could be better but my first attempt with a table saw

I have a sequencer to fit inside the case and few odds and ends to tidy up

[Techman]

[peAk]

Very Nice!

[InfraXpert]

[nickster]

[wahee]

Many thanks guys.
About the switches. They are the mouser ones. They are a little small for the moog panel but used a sub frame and painted the surface matt black.

I have now fitted an internal sequencer which uses the display as a pattern window. It's great for a bit of mad knob tweaking

[terracide]

So it does not need separate voicecards? I think I read on an old thread crow talked about it having 16 of them , that kind of threw me off this project.

[sixty_n]

@terracide no, it's just one board. The multiple voicecard one is the crowbx

[terracide]

[jhulk]

16 voices would be for the cs80 project as it uses 8 voices per part

the crowminus is just one pcb and unlike the minimoog every thing is all on the same pcb

[lowell513mx]

[wahee]

[qp]

Finished up the build last night. Just missing the 3392 trans (and a couple pots). Fired right up! Only issue was the cutoff frequency spread was fairly limited. I couldn't get it to close fully without sacrificing the high freq. Swapped out R174 200k with 100k. Totally nails it!!

[s]https://soundcloud.com/laurentide1/crowminius-test-1[/s]
Haven't calabrated it fully yet. Did a little quick "by ear" tweaking for the VCA and filter, but that's it. Not bad out of the box.

Thanks for this Crow!

[tvh]

Qp that sounds great! Inspiring me to finish mine. I put it on the backburner since I've been moving and haven't set up the workstation yet.
Let us know if you have any tips for setting up/calibration - so far I am planning on winging it with the original manual.

[aquatarkus]

Fantastic! Thanks for the upload.

I ordered from the November batch. Looking forward to receiving the board so I can get my order in for components and start building!

My empty Duino case that I bought from Dan and the lcd from Adafruit have arrived already.

[qp]

[qp]

[aquatarkus]

I searched on the internet and found this page:

http://duinokit.com/ShowAndTell/viewtopic.php?t=34&p=64

So I emailed Dan at Support@duinokit.com and asked if he had any more blanks.

He said he had 9 left (probably 8 now since he sold me one). It was 43.55 USD with shipping.

I searched the thread and Crow's site for the fpd file for the panel crow used in the kit but couldn't find it. Did I miss it on the thread??

Jim

[aquatarkus]

Here are some pics

[qp]

[aquatarkus]

I was surprised at how tiny it was. It's about 9" x 15". For some reason I was expecting something a little bigger. But yes - it's a nice little case.

...and I will probably add some sticker art to it!

[qp]

[aquatarkus]

[qp]

[aquatarkus]

Sorry! just double checked...it's about an inch. Was looking at it from a bad angle.[/quote]

[qp]

[oldcrow]

Nice job on the build and sound.

You do not have to remove the rotary switches, the lid will close fine, provided use you a shallow knob. I used the PKES type Small BEar sold on the SMT version without any clearance issues. --Crow

/**/

[qp]

[oldcrow]

I gave all the trimmers the same reference designators (R31, etc) so as to make using a mini's service manual easier. The only difference is I call SHIFT "ZERO" and HI END "HI COMP" for each osc.

--Crow
/**/

[qp]

[tvh]

Thank you qp - That is extremely helpful!

I am going the midi to V/Oct route but looks like most of your steps are the same.

[aquatarkus]

As I gather parts before my board gets here - I have a quick question. I plan on building the suitcase version like Crow's. I've bought the LCD from Adafruit - but I didn't buy an Arduino b/c I was unsure if I needed it.

Do I need to buy the Arduino Uno to go under the LCD as well? Or does the LCD package fit on the board without the Arduino?

[oldcrow]

You do not need an Arduino, the microcontroller is already on the Crowminius board. The LCD header pins on the Crowminius board have an Arduino Uno spacing, so you just use a set of male headers on one (LCD or Crowminius) and a set of female headers on the other.

[aquatarkus]

[qp]

nevermind....

[sduck]

Ummmm, is there going to be another run of these boards? The through hole kind?

[qp]

[sduck]

[OrganFixer]

Does anyone know if the mid November batch is shipping yet? I haven't heard anything about my order. I'm worried my order might have gotten missed.

[samuraipizzacat29]

[aquatarkus]

OrganFixer

I'm waiting as well and haven't heard anything.

[qp]

some more beefy goodness. Testing out the filter overload. Sent the Low Out to the Audio IN.

[s]https://soundcloud.com/laurentide1/crowminius-test-2[/s]

[aquatarkus]

That sounds pretty fat!

[colorbars]

[oldcrow]

The board order got delayed courtesy of the US postal service. It has sat in some warehouse in California for two weeks now.
The moment I get them they will ship out immediately. I have ordered a provisional backup batch (*not* shipped by USPS) just in case.
I want everyone to have Christmas presents.

--Crow
/**/

[oldcrow]

I plan to offer a small batch of the SMT variant for DIY. I am trying to get the pending through-hole orders filled first, given the postal delay. --Crow

[oldcrow]

The onboard pitch DAC uses a 4.096v reference, so I have to scale the response to 0.8v/Oct. You *can* use a 1v/Oct reponse for the onboard system by sacrificing an octave of range. You have to select R4 as 121K and recalibrate for four octaves in the AVR code.

[OrganFixer]

Hi Old Crow,

Thanks for the update. The delay is no problem for as I am not going to build this until sometime next year. I was just wondering about the status since I hadn't heard anything.

btw - I remember years ago getting some help from you when I fixed a polysix battery leak using the information on the "Old Crow's Nest" website.

[oldcrow]

I didn't mention it here as it isn't going to be marketed as DIY, but I am making a euro version of crowminius split into two modules, "A" (osc/mod) and "B" (filter/EG/amp). I will have these pre-assembled once I hammer out the logistics of building the desktop crowminius and the euro modules as they both use 90% of the same parts.

https://www.muffwiggler.com/forum/viewtopic.php?t=149541

FYI, Crow
/**/

[sduck]

Will there be any more through hole boards? Or any possible left overs from this current batch available?

[oldcrow]

There will be more once I get this latest order in. --Crow

[aquatarkus]

Hey Crow -

I looked through the whole thread and didn't find anything about this so I thought I would ask.

Can you give a link or part number to the toggle switches you are using in the Crowminius Euro and suitcase w/the the front panel.

Currently the BOM has these: https://www.digikey.com/product-search/en?keywords=ckn9545-nd

Thanks!

[oldcrow]

The SMT Crowminius and Crowminius Euro use the E-Switch
200MSP1T1B1M2QEH http://www.digikey.com/product-search/en?keywords=EG2447

Please note my boards for the crowminius euro and SMT desktop are designed for these switches, the switches are not going to fit in a v1.1.2 desktop board unless a 2mm to 2.54mm harness is used.

I am working on a set of plastic switch actuators that clip onto the top of the CKN9545 switch so they can be used with a panel.

--Crow
/**/

[aquatarkus]

[lincolnic]

Hey Crow,

Back in August you mentioned you'd be making a front panel for the 1.1.x version of these boards, but I haven't been able to find any mention of it since. Is this still in the works? Thanks!

[Synthsense]

I'd like to make you a question too Crow:

Do you plan a control board to make the Crowminius polyphonic sometime in the near future?

[oldcrow]

That would be a tall order. Unlike crowbx, the circuits for crowminius are not designed with programmable-presets or polyphony in mind. Now, I *could* redesign them for that, but that would be waaaay down the road.

Now if you want to use a 4-channel MIDICV unit and four crowminius units, sure you can do a 4-voice.

[oldcrow]

Yeah I got caught up in getting things ready for Knobcon, then Crowminius Euro and then getting crOwBX Euro closer to batch 1 production that I sort of let this one languish a bit. I can tweak the panel for it this week, but after I ship out the final eight crowminius boards of the year. --Crow

[stringsthings]

also interested in the next batch of thru-hole pcbs.

[colorbars]

Finally finished my build, everything seems to work except I have no sound from OSC 2. I've checked to make sure the OSC 2 on/off switch works and checked for obvious issues like orientation of caps, diodes, ic's etc but other than that I'm a little lost as how to troubleshoot this. Would really appreciate any help.

[spneca]

qp,

Could you share the part number for the switches that mount underneath the board?

[oldcrow]

Hm, check the orientation of FET Q9. The flat side should face toward the 4 o'clock position. Check that an IC pin didn't get left unsoldered too.

--Crow
/**/

[lincolnic]

[oldcrow]

Jameco Part no. 2167533

[colorbars]

[peAk]

So I am having an issue in the power section. (I believe)

I am running one 12v adapter on the bottom jack. Both my Positive and Negative LEDs are lighting up. I am not getting much (just mV) voltage to all three op-amps. Adjusting the power trims don’t have any effect on the voltage readings either. I have tried the jumpers both horizontal as well as vertical. I have done a quick check to make sure all diodes and transistors are correctly oriented as well as reflowed the pads in the power section. I have disconnected all the wiring with the same results.

What are some things I can check within the power section to help narrow down what might be the issue? Again, I have temporarily disconnected all switches, pots and jacks so the test would be done without them but I can easily connect anything should I need to. Besides the main jumper in the power section, is there anything else that needs a jumper? Just looking for some ideas.

Side note: The only other LED to light up when everything was connected was the Overload LED.

Appreciate any and all suggestions

[spneca]

[colorbars]

I've got OSC 2 working now, found an unsoldered pin on one of the rotary switches which I'm guessing was the issue.

For the USB midi in... Could I use an adapter like this to use/power a small USB keyboard like a qunexus or korg nanokeys etc?

[oldcrow]

The USB code is not ready yet. Also, it will not be a host device when the code is ready, so you cannot directly connect a usb input device.

[peAk]

Okay, so I worked through the power issue. Friggin cold solder joint on leg of TIP32.

Trimmed my power to -10/10 and all of my chips seemed to be getting the appropriate voltage. So now all my LEDs are lighting, midi input seems to be working, A440 Test Tone works, but I am only getting a really faint sound through the output that I have to really crank up my mixer to hear. Nothing through the headphones. The sound seems to be affected by the obvious controls like modulations, cutoff, etc. In some settings my midi notes would just click. Adjusting some of the trimmers would affect the sound some but nothing changed the extremely low output. (Test Tone Volume Normal though)

My next step is to reflow all the pads on the board but was curious if there was anything else to check before that?

Crow, any ideas? All FETs are clocked appropriately

Also besides J2 & J3, are there ANY other jacks that need to be jumped in order to work? I have pins and headers on everything but as I am testing the least I have to reconnect, the better.

[oldcrow]

This sounds like the VCA contour voltage to the VCA is not getting there. A440 happens after the VCA so the final output stage seems OK. If you set the VCA contour attack and decay to minimum (CCW) and sustain to maximum (CW) and measure the VCA contour CV at the lower lead of R180 (see image) to ground, what value do you get with a key pressed?

[oldcrow]

My cases have arrived!

I still have a pre-order slots available for the Crowminius Desktop. (I am building those already pre-ordered.) Now I just need the front panels.

[peAk]

[peAk]

Crow, after getting that voltage reading for you yesterday evening, I was adjusting some things and surprisingly got a (unintentional) signal from my s-trigger.

I was able to get a solid, infinite tone (fat Moog) from oscillator 1 that was of normal volume and that responded to the filter, pitch, etc.

So I am assuming that my midi to cv is not working since the voltage reading you asked me to get wasn't affected by midi and midi notes won't trigger the oscillators. I assumed that midi was working because I was getting midi on/off notes on the TX LED but that's obviously not the case.

I did get the preprogammed chip from you so I should be good there.

Any ideas what I can check now?

[peAk]

Okay Crow, just an update. I disconnected the S-trigger jack

Now when I measure R180 its (-).400 volts at idle and when a key is pressed it jumps to (+)9.00 volts

only sound I am hearing is a click when I hit a key. This sound is present even when I turn the osc off.

Are there any jumpers that are needed for midi to cv? I see all kinds of jumper pads next to the atmel chip but all the info I could find in this thread and your bom seem to have me thinking this is just for use with the LCD. Also, the resistor next to the vactrol is open. Does this need a jumper?

Just looking for any clues.

[oldcrow]

If the Tx LED flickers it means the micro is processing the messages; it is not a passive MIDI indicator.

I gather you have EXT GATE jack J14 installed as omitting it would prevent the MIDI-gate from reaching the envelope generators. If the EG is reacting (+9V) then it seems the gate is working--does the gate LED light up?

There are no jumpers aside from glide lock disable which would not affect this. Those pads are for the optional LCD which is not needed to operate the instrument.

The vactrol trim resistor is not needed and wouldn't affect this anyway.

Make sure D19 is not installed backward.

I'll think more on what is happening here. --Crow

[oldcrow]

You can trim this click (it is VCA control voltage feedthrough) for minimal level using the VCA BAL 1 and VCA BAL 2 trimmers. FYI.

[peAk]

Finally!!!


She works!!!!

Don't ask me what I did cause I did a bunch of things while it was unhooked. I reflowed the inputs and outputs. I also reflowed a few questionable ones under magnification.

All I know is when I hooked everything back up and powered her up, we had some magic.

Merry Christmas to me!!

Thanks Crow, and sorry for being bothersome

[oldcrow]

Merry Christmas, rebel scum!

[peAk]

Hey Crow,

So I am trying to calibrate this and Osc 1 seems to be giving me some issues (2 & 3 seem okay)

1. The tracking/scale is really compressed no matter where I seem to set the trimmers at. Within like 4-5 consecutive keys, it will travel through many octaves. Adjusting the (multi-turn) trimmers doesn't seem to stretch it out any, just mainly moves it up and down the keys. Again 2 & 3 seem fine.

2. The oscillator also drifts quite a bit. Like not quite a whole note but a pretty large amount in a pretty short amount of time. Almost like its modulating (All modulation is off). Osc 2 & 3 are dead on and don't drift at all.

Things I have double checked are:

Trimmers R14, R16, R18 are correct
R13, R17, R19, R21, and are R23 are correct

I used 1K SMD tempcos under the LM3046
Used 23.2K resistors for R23, R63, R101A

Connecting through Midi Din and R4 is 102K

Just looking for some other ideas to check.

[peAk]

also, just to add...

On my LM3046 Pin 5 I am getting a reading of 8.4volts, whereas Osc 2 & 3 I am getting 0 volts on pin 5.

Not sure if that means anything?

[oldcrow]

Hm, check R22, R28, R30. Verify Diode D2 is correct orientation. 8.4v on that transistor is definitely abnormal. --Crow

[peAk]

[oldcrow]

That sets the octave ranging reference voltage to exactly -5.00v. If your octaves are dialing in correctly, no need to adjust it.

[peAk]

Crow, can you tell me hypothetically what would happen if say the smd tempco wasn't properly soldered to ground under the LM3046? What kind of behavior might happen?

And would there be any way to test if the tempco was properly soldered underneath the IC?

Just trying to rule certain things out here.

[peAk]

Crow, I am trying to compare both good oscillators circuits (2 & 3) to try and track whats going on with Osc 1. I am checking everything and trying to point out where I am seeing large differences.

On Osc 1 (LM1458) pin 1, I am getting a -.91mV

whereas on Osc 2 (LM1458) pin 1, I am getting 4.8V and on Osc 3 (LM1458) pin 1, I am getting 2.6V

Does this mean anything?

And if you have any other places I can check within the Osc 1 circuit, please let me know.

[oldcrow]

Which IC number? Guessing IC4. That is the triangle waveform output. Even when the oscillator is running out of spec, does it provide all waveforms? It may be the 3046 is defective.

Other things to check:

Is the voltage at IC4 pin 7 close to 5.00v?

Are +10v and -10v appearing on the op-amp supply pins for IC4, IC6, IC8?

With the power off, what resistance value do you measure across the pads for R24? These are the pads for the throughhole option of the 1K 3300ppm resistor. The value should measure something near 1000 Ohms.

--Crow
/**/

[peAk]

[oldcrow]

There you go. The 1K 3300ppm part is not ringing out. Pull the 3046, touch up the solder (I tend to forget an SMT pad to solder now and then), install a fresh 3046 and save the old one for evil experiments. Check the 1K measurement before installing the new 3046.

[peAk]

just an update, like you said, it was the tempco.

There are very few other things in life that I would rather not do than remove a 14 pin IC from a PCB but hey....

it worked


All Oscillators are stable and can be calibrated.

I fully recommend anyone who hasn't built this yet that plans to use SMD tempcos to check and make sure the resistance is correct before soldering these chips on top of them.

[peAk]

Crow,

I am having trouble getting Osc 3 calibrated correctly. I am running just a little shy on my SCALE trimmer.

Even when I get it as close to scaled as possible, I can't get the Octave/Ranges calibrated. I run out of room on the trimmers there as well.

Osc 1 & 2 are fine - both scaled properly as well as Oct/range calibrated, it's just Osc 3 that I can't get.

I have already checked the component values within Osc 3 and all checked out okay.

I am using midi so R4 is currently 102k.

Do you know of anything that would throw 3 off and not 1 & 2? Modulation is turned off.

[peAk]

Crow, still can't figure it out here.

Got anything I can check, any voltage I can read, just anything really.

Is it at all possible that all the tolerances added up here?

I am so close to having this thing finished if I can just get this last oscillator 3 fully calibrated.

Is there another possible value I can use for R4? I even tried a 120k out of desperation but that obviously didn't work.

[oldcrow]

Hm, if just osc3 is off-spec changing R4 is not what you want. What resistance do you measure across the scale 3 trimmer (R91)? If it is close to zero ohms then you can try changing R94 to 95K or so (pull up one leg of R94, solder it to one leg of a 4.99K resistor, solder other end of 4.99K resistor into free pad) and try to dial in the scaling.

Not quite sure why it would be out of spec, are resistors R93 to R99 the proper values?

[oozitron]

Any suggested way to make the Glide turn on with a gate?

Not controlling the *amount* of glide, just switching it on.

Drew

[oldcrow]

You could place an analog switch across the glide switch, something like one section of a CD4066, then a gate signal through a series resistor and clamp diodes would operate it. You could also use a FET switch, but it would need enough extra parts that the IC is easier to deal with. You would want to operate the IC from the +5v and -10v rails. --Crow

[peAk]

[peAk]

Is it possible to try 5k in the other direction? Like pull out the 90k and 5k and maybe try 85k or something close?

It seems like adding the 5k put me a little farther out in the wrong direction.

[captnapalm]

FWIW, I'm having a similar problem with my osc2 calibration.

[peAk]

Okay Crow....

I don't want to jinx myself like I have seemed to do here lately but I believe I fixed it. At least all of my oscillators are fully calibrated across all the range/octaves.

I ended up socketing R94 and trying a 82k resistor there and that did the trick.

I am not sure if this was a component out of spec or a tolerance stack-up but whatever happened, it seems to be fixed now.

I just wanted to report back in case this can possible fix captnapalm or anyone else having oscillator calibration issues.

[peAk]

Crow,

What is the current status of pitch and modulation over midi with the chips you sold?

If it is not currently working, will you still be adding it in the near future? I know you mentioned it early on but I also know you have been busy with other things. If so, will you be selling that (new) chip like you sold the last one?

I am trying to finish my panel design but a lot depends on whether midi will support pitch and modulation. Modulation with a pot/knob is fine but for pitch it's definitely not ideal.

Any information on this would be greatly appreciated.

[stringsthings]

Just ordered a PCB from the Q1 2016 Batch

[aquatarkus]

FYI -

Putting my BOM together at Digi-Key and these parts are out of stock:

2.32k 1/4W 1% resistor

8.2 OHM 1/4W 5%

Crystals 16MHz 20pF

TL1107AF180WQ switch

.1uF 10% 250VDC Cap

EDIT: forgot one: 609-3242-ND four pin jumper. I just used this one: 609-3201-ND

Found all of the above (exact parts) at Mouser.

Crow - P4519-ND (.033uF 5% 50V) is gone. Will this work: 495-5024-1-ND?


One more order from Thonk and then it's just waiting for parts to begin...

[peAk]

[oberling]

[peAk]

[oldcrow]

This is in fact what I did for the SMT version: use two dual DACs. I will try to devise a retofit board for the v1.1/v1.1.2 Crowminius boards. It would add the 2nd DAC and a simple VCA to do pitchbend/modwheel over MIDI pretty well. Too bad Microchip does not make a 4-channel SPI DAC. They made an I2C one, but the data speed is too slow.

[aquatarkus]

Hey Crow -

I'm building the ARP 1601 sequencer clone when the 3rd run is available a little bit later. I was hoping to use it with the Crowminius, but after reading online it looks like the gate voltages are different.

The creator of the 1601 project said,

"I think you'd need to find out from the relevant developer/supplier of your intended modules whether a +14V gate is OK or too high, in which case a simple resistor/zener diode network, which you could even build into a plastic 3.5mm jack plug on a special patch cable, would do the trick. Failing that it would be quite easy to make up a simple voltage reducer for all these signals on a bit of strip board."

So - would the +14V gate be too high for the Crowminius and will I need to come up with a way to step that down to use with this synth?

Thanks!

[oldcrow]

+14V gate would not harm anything, but it might make the EG action a bit strange as the input voltage would be greater that the supply rail. The easiest solution would be a 5.1v zener across C95 (anode to ground). This would clamp any voltages past 5.1v. --Crow

[aquatarkus]

Thanks!

[oberling]

My 5U 19"frontpanel arrived and I'm pretty stunned (although there are minor design errors on it which took only seconds to fix; and one female connector fell off which was unexpected - but I'll sort that out with schaeffer ag)...

If someone wishes to use it - go for it: crowminius_minimoog_rme.fpd ... but be prepared: it's quite expensive!
A comment on the hole below the display section: this is meant to be used for buttons (maybe change some parameters in the firmware - have a menu for some sort of things like assinging a different MIDI channel or something) and the to-be-designed PCB for them could fit the lower display connectors.
Comment on the display section: make sure the position of the connectors relative to the actual display match your specific display as there are differences (I took the measurements of the adafruit display from the display kit)

I did not include Pitchbend and Modwheel as I plan to use it MIDI-only and have a second DAC piggybacked on the first one (as elaborated in my post above) - also the frontpanel is packed already... no room left .

The rocker switches I use are "KND2 2X2" from Daier via alibaba.com. This was the hardest part in sourcing for this project so far and I'm not completely satisfied with them as they all have a red dot on them which I scraped down carefully with a knife. But they fit perfectly - so I've got that going... which is nice




I plan to house the PCB behind it is using some bent aluminum sort of case with all the Audio- and MIDI connectors that has to be attached to the frontpanel "somehow" - that's up to future oberling to solve
Also I hope nothing is missing

[peAk]

that looks fantastic!

I am going to import it into FPE just to see the price

[peAk]

I just saw the price

[oldcrow]

Actually, with a bit of Inkscape editing, I was able to get the price down below $300. Making all the graphics a single hpgl object saves a ton on panels. Also you can specify no infill and do that yourself.

[Altitude909]

Once the engraving crosses the $125, you're better off getting them silk screened (that's the normal setup cost). $517 for a panel is nuts. Someone should hit up Heinz at CAM expert, he's consistently %25 cheaper than FPE

[nickster]

I would recommend folks to head over to Re Synthesis they do excellent panel work at very reasonable prices. My panel was quoted for around $120 but this was a "guesstimate" so expect some rise in the final cost. Also as you can imagine there are a number of variables that will affect final price not in the least shipping.

http://www.bigbluewave.co.uk/resynthesis/resynthesis_home.htm

[peAk]

[Paradigm X]

OT: Sorry, oldcrow, could i suggest you put a link to your site in your sig ? Im always reading about youre cool projects and have to go and google them (#firstworldproblems i know).

many thanks

[thesoundfarmer]

Hi everyone,

I need some troubleshooting advice I'm afraid.
I've completed soldering all the components and added a jumper for the power supply.

I did make a couple of mistakes with the board which I have corrected but not without damaging a couple of traces and through holes. As far as I'm aware I've patched these up and tested continuity fine.

When I plug in my PSU the only LED that lights is "Phase".

There is no pilot tone, and when I play the keyboard (via midi CV converter) only oscillators 1 and 2 make sound. No matter what keys I press only the keyboard it's always the same note.

Filters and ADSR all seem to work which is something!

I'm still pretty new to electronics, does anyone have any advice or ideas what may be amiss?

Thanks!

Greg

[peAk]

Hey Greg,

Just wanted to say that I had similar problems that you are experiencing and they all worked out.

AFAIK, unless you are running two 12v adapters, the phase light shouldn't be on. It's actually the only one that doesn't light up. Make sure and check your jumpers, they should be running left to right. Again, this is if you are running one 12v adapter.

Do you have off board wiring? I, too, would get just one note playing and it was because of the wiring and something shorting something else out. I would move my wiring a little bit and it would stop and then it would come back, so definitely check that. Also, make sure that your switches are correctly wired.

You are off to a much better start that I had so definitely keep troubleshooting. I spent over a month troubleshooting Make sure and read over every page on this thread because there is a ton of information to sort through.

[captnapalm]

I had a problem of the same note always playing, and it was due to not installing the glide lock components. Crow mentioned a jumper that's needed if the glide lock isn't installed.

[thesoundfarmer]

Typical that my phase LED is the only one lighting up when it shouldn't be! Looks like my jumper is incorrect. (I've gone B/A)

I've jumpered IC25 as I'm not using glide lock.

I've no off board wiring but I'll double check nothing's shorting.

After looking through the forum and again at my board I've determined the following:

I'm missing a 1k trim pot at R384.

As I'm using CV and not Midi it looks like I need to change R4 from 102k to 121k resistor.

I have a horrible feeling the majority of my LEDs are the wrong way around. Also I didn't use the ones on the BOM, just a load from Maplin of various colours. Would either of these make a difference?

Also I socketed the CA3046s. One post is saying not to, but a later one is saying it doesn't really matter. I'm not all that keen to remove the sockets as every time I have to remove something I end up damaging the board, but I will if I have to!

Greg

[peAk]

Crow mentioned there was a small advantage gain from not socketing the 3 LM3046 but it's not crucial.

Per Crow:

You can socket all of the chips if you want. The VCO 3046s gain a small advantage in not being socketed but most of the temperature equalization between the 3046 and the tempco is made through the circuit trace, given the tiny thermal mass of the tempco.

Did you use the through-hole tempco resistors or the SMD underneath?

All of the LEDs cathodes (flat side) are facing down.

[thesoundfarmer]

Thanks for your replies!

I used the SMD. I'm fairly confident they're OK, fiddly things!
I'll reverse the LEDs. Hopefully that'll solve a couple of the problems.

[peAk]

Crow, I am implementing a pitch and mod wheel on my Crowminius.

My pitch wheel has a spring but I was thinking about adding a "dead zone" with pair of paralleled diodes (4148s)

Do you see any problem with this? Or suggest anything different?

[peAk]

Crow, the mod I am asking about is the mod on the far right second from the bottom. Do you see any issues with this and the Crowminius?

[oldcrow]

This should work fine. --Crow

[oldcrow]

Hey folks, I've been busy but managed to get the 3D-printed switch caps underway. These are draft prints but will work with the front panel for v1.1/v1.1.2 boards. More soon.

[oldcrow]

I will be launching a kickstarter to build desktop Crowminius units. Watch this space.

[killbot]

cool, can people who have so far only purchased the board be able to buy the rest of the desktop unit?

[InfraXpert]

[oberling]

[mOBiTh]

you can export hpgl from front design no?

[oberling]

I think I figured out how to do this:
1. export the frontpanel as svg graphic
2. import this svg into inkscape (for it can export hpgl files)
3. remove all non-printed objects including every cross that's visible - all visible objects in your inkscape file will be visible in the hpgl file
4. export as hpgl
5. in frontpanel designer remove all printed elements that reside in your hpgl file now
6. add hpgl object to frontpanel and resize/rotate etc. it accordingly to fit everything

Don't be confused if the fonts are completely out of shape in inkscape: they will be just fine when re-imported as hpgl file into frontpanel designer.
As steps 3 and 5 seem to be quite time consuming I didn't do it by now - maybe future oberling will have more time for it... or someone around here

[samuraipizzacat29]

I hate inkscape. If you have a system that can run it, illustrator cs2 can be found on the internets by legitimate means. it will require some googling and effort, but it can be had.

[oberling]

[oldcrow]

Hey folks, the Crowminius board batch for Q1 2016 is finally here. Over half are already sold, so get em while the gettin's good.

[peAk]

Hey Crow,

I am finishing up my build and I am having one last issue that I am trying to work out. I thought I had the thing calibrated okay but once I put it all in my enclosure and got my pitch wheel and tune knob centered, I needed to adjust the calibration again.

I am having a little trouble with oscillator 3 again. Last time I was having trouble scaling it right and by changing R94 out to a 85K, I was able to get it scaled properly. This time I can't seem to get the range in tune at 32' through 2'. My scale is fine but I seem to run out of room on my zero and octave trimmers while setting the range. I always run a little flat no matter where I set them. Is it possible to adjust R93 or R95, similar how I adjusted R94, to get the range to calibrate?

Any help would be great.

See below to see how close I am to having this thing done

[dalhasumai]

I would like one please !

[peAk]

Crow

Any ideas how to "tame" attack the modulation pot some?

I have a A50K attached to a mod wheel but it seems very sensitive in the beginning of the rotation. Like kind of hard to dial a vibrato in before it's too extreme.

I am not sure exactly what the pot taper was like on the original Minimoog but from the videos I have seen, it seems more subtle until you get more than half way up on the wheel.

Not sure if I need to hunt down an original pot or if there is some tweaking you can do to this?

[peAk]

just to add, all the pictures of the original minimoog modulation I have seen show only two wires connected to the pot, is this how the crowminius should be wired?

[NLS]

Hello there!

Would it be okay if I use 4.7K trimmers instead of 5K like on the BOM??

[Techman]

[tvh]

peak that is a thing of beauty

[wahee]

Peak you nailed it with that design, really nice

[peAk]

Thanks guys

Just an update:

I found this info on old moog forum:

"The mod-pot has only two wires. In full counter-Clockwise postion it should have 0 Ohms. Fully forward (full modulation) it should have 1,2 KOhm. This is a movement of 90 degrees - it´s a miracle, that this 50Kohm-Pot (audio/log) makes only 1,2 Kohms at the first 90 degrees...this is really special. So it will not work if you change it to a simple 50KOhm log Pot. "

I searched hi and low for a suitable pot for the modulation wheel with little success. The tapers on almost every 50K pot just weren't right. It ramped up just too fast. I had a Burns A25K that had a pretty good taper but it just wouldn't get to 0ohms to close the modulation and so the bleedthrough was just unbearable.

Here is some great information from Synthfool (RIP) about some ways to get rid of modulation bleedthrough on the minimoog:

http://www.synthfool.com/docs/Moog/minimoog/modwheelfixes/

In the end, I ended up getting a suitable potentiometer from CAE Sound for a Minimoog replacement pot ($30 pot plus $12 shipping) .....but it's a pretty hi-end pot and got me what I needed (very little bleed and correct taper)

So hopefully this info can help someone that goes through this.

I am finishing up now just waiting to get the back panel fabricated.

[samuraipizzacat29]

As a possible solution you could take a pot apart and drop a glob of solder or something over the very end of the resistance disk. The solder will wear over time, but is a fairly easy fix. I would imagine silver solder would hold up slightly better over time.

[peAk]

[wahee]

[peAk]

Even with this new pot, I still get a little bleed. It's not too bothersome but it's there.

No, I don't think pitch and modulation were ever implemented over midi. Crow did say there was a work around but it was a little above my head. I got tired of waiting and just decided to use on onboard modulation and pitch pots and wire them directly to wheel assemblies. Obviously this isn't ideal because I can't record and automate like I would be able to if it was midi but I can live with it.

I have been tweaking mine for months and really, REALLY comparing it to Minimoog videos/audio I can find online. There is one youtube video that a guy did where he runs through each and every Minimoog patch and plays it after showing each patch. It's a real good way to compare. Obviously even Minimoogs sound different from each other so none are going to sound exactly alike. I never heard a patch that I couldn't nail even if I had to adjust mine slightly from the patch sheet.

Besides the issues I mentioned previous, I am really happy with everything. I think it sounds fantastic, goes in tune very quickly, stays in tune all day. I wasn't able to get the filter to scale across the octaves correctly but I also didn't spend too long trying. I may revisit it at some point.

[wahee]

haha - I have just been watching the same videos on YouTube and I must say now I have tweaked the filter, it's pretty close. It requires a bit more tweaking on the controls to get the attack and punch right of some of the bass sounds but overall great. I also discovered some of my switches were wired back to front. No big deal though.




The midi mod is not such a big deal although like you, programming it in a DAW is handy.

I love my crowminius and it's been a really great experience to build. It now sounds fantastic.

I was looking at the mods you listed a few posts back. I love SYNC effects and was thinking of trying the mod on the crowminius. Presumably the new OSC mini boards version.

From a quick glance at the PCB is seems that IC8 is the same. Is Q9 the same as Q9 on crowminius I wonder. Having a look now

[stringsthings]

I have a few questions on the value of some resistors. ( REV 1.1.3 )

R22, R62, R100, R378 are listed as 15K in the BOM and on the schematic, but on the board R22, R62, R100 are printed as 0? And R378 is printed as 10K?

Also, R7 is listed as 22K in the BOM and the schematic, but it is printed on the board as 0?

[oldcrow]

Grumble, once again MW is not sending me email notifications.

I will edit an addendum for the v1.1.3 boards, which use an extra bit of circuitry. For R7, R22, R62 and R100 if the opamps they conenct to are 1458s, use 15K. If you use TL072s, they can be jumpered (zero ohms). Either way is fine.

R378 should be 10K.

--Crow
/**/

[gruvsyco]

I'm currently building my V1.1.2.

I'm curious how difficult would it be to modify/adapt this to be full on semi-modular?

[p4rancesc0]

[oldcrow]

FYI my kickstarter is now LIVE!

Link is available from http://www.crowmini.us/

The kickstarter DIY PCB release is the same through-hole board. The pre-assembled Crowminius will be the exact same circuits, just in SMT for assembly efficiency. --Crow

[sine]

http://www.cs80.com/crowminius/CrowminiusDemo01.mp3

This sounds like a minimoog.

[sine]

Sorry if this is a dumb question as I don't much about electronics, but why are the PCB jacks for EXT GLIDE ENABLE and EXT DECAY MUTE TRS instead of TS?

[sine]

Another question: Are the case hinges "break-away" so the lid can be removed?

[gruvsyco]

Is there an off the shelf wall wart that works for these. Everything I seem to be finding is 12VDC.

[oldcrow]

This is a minimoog thing. The idea is to allow the option of using a foot pedal for changing the glide rate (not a volume pedal, but one wired for this). The minimoog used a smaller (0.206" dia) TRS jack for these options. Early minimoogs used momentary switches, not jacks.

[oldcrow]

I use this one,

http://www.mouser.com/ProductDetail/Triad-Magnetics/WAU12-500/?qs=Ne5J DZsVItYeuvc0Wnc7cg%3d%3d

[gruvsyco]

[numbersix]

[medbot]

If I had the money to build another one I would make it semi or fully modular using switching jacks so with nothing plugged in it would operate as normal. Basically a Minimoog 2600. It wouldn't be (too) difficult if you can read the schematics and aren't afraid to cut a few traces.

[sk23]

Hello,

I would like to know if with the 1.1 version and so with the ATMega programmed and shipped at that time, we can automate via midi (no CV):

1) filter cutoff
2) pitch bend

I would also like to know if the Crowminius is capable of making slide between notes and the velocity affect the filter cutoff.
Should be make an operation with the switches to enable it right? Can someone please explain that.


Thank you!

[gruvsyco]

[mrgazak]

[oldcrow]

Crowminius in 5U will use a panel that is 5U x 8MU (8.75 x 17 in.) This way a 5U 19" rack frame adapter can be used. I will try to implement the extra jacks as I did for the euro prototypes. --Crow

[Fiflouc]

Hi Crow, in your kickstarter page your talking about build documentation, is it possible to download it? (I am still populating 1.1...)

Thanks!

[mrgazak]

So, today is the birthday of my late friend, Bob Coleman (synex or realsynex). Although not a member of this forum, he would have loved it.

In honour of the first birthday since he passed away, I've pledged to support the Crowminius DIY bare board and front panel via Kickstarter. Hoping that at least one other friend might take it up too so I might be building more than one.

My day job is buying for a UK electronics assembler so I'll be compiling a BOM for UK component sourcing, if any UK self-builders are interested.

Gareth

[ALTelectric]

Hey Scott, just received my board and MCU, they look awesome! Is there an .fpd you are working from to make the front panels? i want to create my own, but it would be a huge help to have one that works for the appropriate dimensions of the board. I'm thinking i'll probably wire a few controls off board but wanted to keep the oscillator section knobs on board, so a working .fpd or some other sort of documentation for the oscillator section would be a huge help. i'm an infant on Eagle, but i know its possible to take an Eagle design and convert it to an .fpd with a little bit of resizing switch holes. I could, obviously, not be so lazy and work it up on my own, but if you happen to have a solution for me or other suggestions i'd be very appreciative!
Thanks again, this project is fantastic!

[Fiflouc]

Hi again, do some of the transistors need to be matched? I have read most of the 32 pages but I didn ´t find the answer.

Thanks.

[oldcrow]

The only transistors that need matching are already done as the LM3046 parts. Modern discrete devices like new (not NOS) 2N3906s seem to match within 2mV Vbe out of the bag these days.

[Fiflouc]

Ok thanks!

[gruvsyco]

Pardon my enthusiasm but this is my first real synth build.

So excited... I have an almost fully functioning Crowminius! All the oscillators make sound, filter filters, envelopes work, noise is working! it sounds glorious.

It's not tracking pitch via MIDI (it does trigger notes, same pitch across keyboard), I haven't tried CV yet.

[crustibooga]

Was hoping this would be funded by now. Fingers crossed!

https://www.kickstarter.com/projects/1312542133/crowminius-desktop-ana log-music-synthesizer

[oldcrow]

I will be re-launching the kickstarter at a smaller funding goal. I've learned a few things in the past month. I still want to get units built for Knobcon delivery.

[gruvsyco]

Mine still isn't tracking pitch via MIDI or CV, I'm going to try installing the glide lock circuit... it looks like some of the probs people have similar to mine are related to that circuit.

meanwhile I got this case that looks promising. I'm probably going to redo the pots and switches to the lid of the case. $21 @ Amazon.

[oldcrow]

Are you getting changing note voltages at pin 8 of the DAC? Also, do the other pitch controls work such as tune or pitchwheel pot?

There are several points in the pitch CV path that can get interrupted. First is the external CV 1/4" jack, make sure you soldered all the pins and that the tip to tip switch shows continuity. Next, verify IC21 is OK. After that, the external glide jack must have its tip switch properly close when no plug is inserted, so make sure there is continuity from the tip to the tip switch. Make sure that jumper in place of IC25 is from pin 3 to pin 5.

Finally, make sure R4 is good.

[quote="gruvsyco"]Mine still isn't tracking pitch via MIDI or CV, I'm going to try installing the glide lock circuit... it looks like some of the probs people have similar to mine are related to that circuit. /quote]

[gruvsyco]

[oldcrow]

Heya folks,

The Crowminius Kickstarter is back:

https://www.kickstarter.com/projects/1312542133/crowminius-analog-musi c-synthesizer

I've added some new info and will add more as I get the 5U version put together.

Crow
/**/

[Godric]

Hi Crow

Thanks for all your hard work here. There seems to be a bit of confusion with component values (particularly resistors) and the different revisions of the board.

Taking the 1.1.3 TH board - As a general rule is it safe to say that values on the overlay are accurate and correct?

Godric

[Godric]

Hi

Building board 1.1.3 (TH)

I have put all the resistors in from the BOM and find that I have some vacant positions on the board:

R360 and R358 given as 47K on the board and 22k in the schematic
R391 and R395 given as 100k on board, not found on schematic (pdf search)
R359 given as 1k on board 44k on schematic
R362 given as 100r on board "open" on schematic
R379 given as 6k8 on board 10k on schematic
R387 given as 10r on board, not found on schematic
XR104 given as 6k2 on board, 6k04 in BOM and 4k75 on schematic.

Any advice on these gratefully received

Regards

Godric

[oldcrow]

Hi Godric,

R358 and R360 are in fact 47K
R391 and R395 are 100K
R359 is 1K
R362 is 100 ohm
R379 is 6K8
R387 is 10 ohm
XR104 is 6K2

I will add an updated schem to the site.

Crow
/**/

[Godric]

[quote="oldcrow"]Hi Godric,

R358 and R360 are in fact 47K
R391 and R395 are 100K
R359 is 1K
R362 is 100 ohm
R379 is 6K8
R387 is 10 ohm
XR104 is 6K2

I will add an updated schem to the site.

Crow
/**/




Thanks for that - seems the PCB overlay has priority like I suspected.

Cheers

[Godric]

Hi folks

In the BOM it says select for reverse bias characteristics.

Is there a formal way of doing this or is it just a case of putting one in and swapping it out if the noise sucks?

Thanks

[Godric]

Hi folks

on 1.1.3 boards there is a 2n3906 transistor marked q16 which according to the board overlay is inserted rotated (like the J112s) is this correct?

Best

Godric

[Godric]

[oldcrow]

I have a panel file for the v1.1/1.1.2 if you want to give it a try. I'll email it.
One note, you will need to get some switch caps 3D-printed. I'll give you the stl file for that too.

--Crow

[colorbars]

[oldcrow]

I plan to get a Micro3D printer so I can make switch caps. The panel you can order from the file once I post it. --Crow

[Godric]

Godric

[oldcrow]

Oh. a 1.1.3 board. OK I do have a known good file for that --Crow

[BrettAdams]

Hopefully a few more people picking up this awesome synth! 3 more days left on the Kickstarter and I'm super excited about this being my big summer project!!

Brett

[oldcrow]

A little over 2 days left for the Crowminius kickstarter! Almost there!
https://www.kickstarter.com/projects/1312542133/crowminius-analog-musi c-synthesizer

[Godric]

Hi peeps.

Powered up my Crowminius for the first time Friday and the power supply is not quite living up to its name. I have both positive and negative rails, but they are +/- 15 and the trimmers make almost no difference to that, certainly can't trim either rail down to 10V.

Bit of a blow as stuff I build usually works first time. Will have time to start debugging tomorrow - but any suggestions? Also what are the best points to measure the voltages?

Best regards

Godric

[oldcrow]

Hi Godric, send me a detail image of the power supply corner. That sounds like the zener diode reference is not working. --Crow

[Godric]

Hi Crow

I swapped the Zener which made no difference and then became suspicious of the two 3906s bonded together (carelessley I pushed them together *after* soldering so I think I strained a leg on one of them), so I replaced them and that fixed it.

Thanks for the pointer. So tomorrow I will populate the board with chips and see how much further I can get.

Regards

Godric

[oldcrow]

Less than 24 hours remain for the Crowminius kickstarter! It has met the goal and going to happen, so if you want one the clocking ticking fast.

[m0d]

Congratulations, oldcrow!

[pix]

Congratulations! is there a way to purchase euro PCBs, and not the full modules? Or maybe euro PCBs + panels?

[Godric]

This is my take on the panel based on the short version Old Crow generously supplied.

I'd appreciate any comments on this, particularly the names for the input output sockets at the left end - this is my understanding of what the sockets on the board are for.

Any other comments welcome.

Best regards

Godric

[blandoon]

Hi Crow,

Do you happen to have an image of the panel that will ship out with the Kickstarter DIY boards? Or would you be willing to email the file, if there is one?

Stoked to see the Kickstarter got funded; I guess this means it's time to get serious about planning for a case and ordering parts

[oldcrow]

I will post that when it is finished. I have to make one and proof it first. --Crow

[BrettAdams]

First off, congratulations Crow on the Kickstarter success!

I am working my way through sourcing all the parts, and was just curious will using all 1% resistors effect the sound at all? The BOM has a mixture between 5% and 1% resistors and I have only been stockpiling 1% since the price difference is minimal.

Is it ok to just use all 1% for the entire build?

Thanks!

[oldcrow]

1% parts are fine throughout. I do recommend 0.1% resistors for the 1K values into the octave selectors, but not strictly necessary. --Crow

[BrettAdams]

Awesome! Thanks Crow!!! Super excited about this build.

[Godric]

Hi

Started testing the crowminius today.

PSU is good. It looks like I have the three oscillators oscillating (although osc 3 seems way low even in its "VCO" position). Oscillators change freq with incoming CV and Octave/tune controls. A range of waveforms appears including PWM. The gate light comes on and I can see a 10V or so envelope on R180. A=440 works.

All good news.

However Noise generator is not obliging and I can hear nothing through the filter.

If I look the other side of the 33k on any oscillator (the audio mix bus) I see a very tiny, noisy version of the oscillator(s) signal. I currently have all the filter trimmers in mid position. I see no signal on either r142 or r177.

If I set the decay very short I get an obliging thump which I have reduced to a minimum with VCA bal 1 (Bal 2 does not seem to do anything in this situation).

Any help gratefully received.

Best regards

Godric

[oldcrow]

You might have the noise diode (transistor) installed incorrectly. It also needs a rotation. I will provide an image when I get back to my home office tomorrow evening. I will post v1.1.3 schematic as well. --Crow

[Godric]

Argghhh Just noticed the B and E marked on the overlay - it might be I can figure that one out. Thanks for the updated schematic

[Godric]

Thanks for that Crow - noise is now working. Just got to figure out what's pulling the audio mix buss down as that is what it looks like.

[Godric]

So if I remove C21 and scope the audiomix bus where the cap was I get correct mixing behaviour with the oscillators/noise. Replace the cap and I get nada at that point. The whole filter block signal path just seems to be grounded. I guess what I could do now is swap out the 3046 from one of the oscillators, any other suggestions?

Godric

[PWM]

Maybe there's a short after C21?
Try to find the problem first. Wouldn't want to destroy another 3046.

[Godric]

The 3046s are socketed for the moment - I wasn't confident about their provenance, so easy enough to swap out.

[PWM]

I understand but what I meant was that there might be a fault in the PCB that could've caused the failure of the 3046 in the first place.
It's not that likely but checking the PCB for errors is worth the part, I think.

[Godric]

Thanks for the comments.

I don't know how reliable the source was for these 'NOS' 3046s, so I am not assuming they are all 100%

Tomorrow I can lift the 3046 and see if the short disappears as that is pretty much the next component in the line. I've checked all the transistors are the right type and examined the PCB for soldering defects and polarised components wrong way round etc. As I can't track signal through the filter starting from its input, it makes faultfinding a tad difficult.

[oldcrow]

Hi Godric,

Check that R67 is 200 ohm, R142 is 470 ohm and the ladder resistors are R105 = 220 ohm, R128, R138, R139, R140 are 150 ohm. 3046s don't typically fail, but it is possible.

Also, do you have J2 installed? The jack switches VCA bias when nothing is plugged in, so you need the jack installed or a jumper from the top pad to the bottom pad. If this is missing the output will always be silent.

The v1.1.3 schem is here:

http://www.crowmini.us/schempdf/Mini_desktop_v113_expomod_sch.pdf

Hope this helps,

Crow
/**/

[stringsthings]

Thanks for posting the 1.1.3 schematic. I'm just finishing up a build and it's great to have the latest schem in case I run into problems.

[Godric]

Hi Crow

Thanks for that info I will check the resistors shortly. I don't have J2 installed but I have already linked the pads as I read the discussion of this point further back in the thread (way ^^^^^^^^ there).

However I now wonder if I am interpreting top and bottom correctly. I have the board with the PSU top right corner, and I have linked the "top" pad of J2 (the one immediately to the left of the electrolytic) to the "bottom" pad (the one directly above T17).

[Godric]

Hi Crow

I checked all the resistors they are all correct.

Best

Godric

[Godric]

As I understand J2, the two 33k resistors should be joined by a link. Is that correct?

Godric

[oldcrow]

Yes, this is correct. --Crow

[Godric]

I have no idea how to proceed. I have been round and checked all components and soldering several times. I may be missing something but I doubt it.

It is almost certainly a dead component but I can't figure out how to narrow it down as the whole of the filter signal path is just dead (signal path has no visible AC on it at all and seems to be 0V).

Really frustrating. I think this is the first of hundreds of projects I have built which has had such an intractable fault (or indeed any fault at all). Last time I had a fault in a project was when I misread a capacitor value in the filter of a Shruthi which made the cut-off point very low - but at least I could hear something (and see with the scope) so I knew that it was probably a wrong value. It may be I've done a similar thing here, but I don't believe I have.

[Godric]

OK I have a more or less working crowminius, that actually sounds like a synthesiser.

I went round and resoldered every joint in the filter/VCA sections. I bloody hate lead-free solder, it's crap.

So now I need to work out why Osc 3 is oscillating but not in the audio range - perversely it actually seems to increase in frequency if I switch it to LFO mode.

Then I just need to calibrate it.

[Godric]

Osc 3 is working - resoldering did the trick again

[Godric]

Does anyone have a specifically crowminius alignment procedure (using the trimmer names that are on the board)? I am finding the Minimoog Service manual procedure hard to apply, partly because of juggling the trimmer names and partly because the minimoog doesn't have a 5-octave keyboard. I am bypassing the on-board midi system and have set the CV in as if it were 1v/8ve (not the .815V/8ve which the onboard midi uses.

For example what voltage would middle A be on an original minimoog? This would help me map the original 3 and a half octave keyboard onto my five octave.

Just asking so I'm not reinventing the wheel.

[peAk]

Hey Crow,

Been using the Crowminius for months and it's great.

I do have one issue that maybe you can make a suggestion to fix?

After it's been on for about 15-20 minutes, I start to get noise from the PW modulation LEDs. If I unhook the LEDs, it goes away but it always comes back if they are hooked up. The noise is consistent with the rate of the PW led blinking.

Any ideas? I have tried running the wire around the board instead of over it but it didn't help.

Again, only after it's been on for 15-20 minutes does the noise start.

[peAk]

Any ideas Crow?

[oldcrow]

Hm, what sort of noise? Make sure your power supply has enough current. --Crow

[richtruss]

Hi,

Please could you advise correct values of:

R200 - I can't read the value on the PCB

R390 -
R392 -
R394 -
R393 -

Many thanks!

[oldcrow]

R200 is 4.02K 1%
R390 is 121K 1%
R392 is 1K 1%
R393 is 1K
R394 is 10K

Crow
/**/

[oldcrow]

I am in the midst of building Crowminius boards for the kickstarter, but later this year I will offer a "mostly" through-hole bare board set for my eurorack version. "Mostly" means there are a few parts that are SMT as they are easier to obtain that way. The euro boards come in pairs: a host board for the controls and jacks, and a voice board for the actual voicing circuits. Since there are two modules--module A is osc bank/modulation, module B is mixer/filter/envelopes/amplifier--this means the there are four boards for the complete Crowminius. Note: this is still a few months out, but as an example here is the actual-size oscillator voice board for module A:



Now back to kickstarter work.

Crow
/**/

[mrgazak]

Hi Crow

Obviously you're incredibly busy with all the Kickstarter stuff but will you have a chance to upload the V1.1.3 PCB component reference layer/silkscreen on here or elsewhere for the lucky through-hole self-builders who are getting prepared for their boards in due course.

It would be great to see the gerber version with its infinite resolution as well as a fixed resolution PDF.

If there are other UK builders, I've compiled a BOM using Farnell UK order codes but there are a couple of anomalies which can be resolved with reference to the layout as well as the schematic already published.

Front panel looks awesome too.

Thanks in advance

Gareth

[oldcrow]

I put the gerber for the silkscreen as well as the v113 schematic in a zipfile:

http://www.crowmini.us/schempdf/Crowminius_v113_refdes_gerber.zip

The unpacked gerber file is 4.3meg, which seems to crash a number of online gerber viewers, but it loads in gview and other apps, as well as sites like paragon robotics' gerber viewer page.

Crow
/**/

[mrgazak]

Crow

Thanks, that's great!

[vilmycil]

Hi all,

I'm still trying to get my build (1.1.2) to work. Didn't have much time but hopefully i shall get there one day!

I have a quick question regarding the crystal. On both sides of the crystal we have a 0.7V Are these values correct? Measuring at atmega.

Thank you!

[oldcrow]

That sounds about right. Is that an ATMEGA part you programmed yourself? I have some info about that near the bottom of the http://www.crowmini.us/ site. --Crow

[vilmycil]

Thanks Crow!

I ordered it pre-programmed. (order reads: Includes pre-programmed MIDI microcontroller). Do you mark it somewhere as programmed? How can I check if firmware is loaded?

Also, does the crystal oscillate all of the time the ATMEGA is powered up
or does it only get enabled at certain times or when certain operations are
done?

Cheers

[mattwa1sh]

Hey peAK that panel is badass. Nice work.

[lincolnic]

So, it's been a long time, but I'm finally getting the funds together for this project. Did these front panels ever materialize? I couldn't find any more info about them in the thread, but I'd really like to get my hands on one. Please tell me it'll still happen!

[richtruss]

Hi Crow,

I've designed a front panel along the lines of the original Model D but with the extra PWM bits. I haven't included for the display as I don't think I'll need to look at that often - but I'm not sure though! What is shown on the display that would be needed on a daily/regular basis? I'm thinking of just having it on the PCB inside the case with easy access - would that do?

Thanks

[Techman]

[oldcrow]

The LCD is for "future evil experiments" It is not necessary. I might implement some adjustable MIDI settings like mod wheel sensitivity, but that is down the road.

[richtruss]

I'm adding a dedicated LFO, Modulation source switches, separate switching for modulation to the VCOs and Sync Osc 3 to 2 - Will take a while to wire it up! Should be ready next year!

[lowell513mx]

I've been trying to figure the wiring for switches for a off board panel. The more I look at the board and try to read schems, the more I'm confusing myself (as I am a sign writer and just a novice with electronics). I thought it was mentioned in this thread somewhere but couldn't find that either. Rev 1.1.2

Some switches only require 3 wires and a few other need more to complete the circuit. I'd like to know if I'm correct on which ones require 6 wire per switch.

Going with the guess that SW8 Noise Pink/White, SW10 OC3 LFO/VCO & SW18 Noise S/H have 6 wires, I thought there was another one though?

3 Wired Switches to be soldered to board orientation to complete circuit?

OOO <---- or
OOO

OOO
OOO <----

[oldcrow]

The only two toggle switches that need two poles/six wires are SW8 and SW10. All the others cane be single-pole/3-wire.

The rotary switches are 2-pole 6-position of course, but you can use 7 wires on the octave selectors per switch as one pole is redundant for better switch reliability. The waveform selectors can get away with using 10 wires each provided you connect positions 4, 5 and 6 to one lead on the waveform side of the switch. In my schematic that is the "A" pole. The "C" pole is for rectangular width.

Hope this helps -- Crow
/**/

[Pioneers]

I'm working on a v1.1.3 board and I'm getting power, both +/-10 volts and 5 volts over to the atmega but no audio. I can get the A440 tone but nothing else . I do see the gate led light when I hit keys on a midi keyboard and I see the led near the atmega flashing. I also see the LFO rate leds blinking. This is after first power up after the build. I haven't touched any of the trimmers other than the voltage ones.

[oldcrow]

Make sure the all 3.5mm and 1/4" jacks are installed. The switched tip is used on many of these and they are needed to close gate, CV and audio paths. --Crow

[Pioneers]

Thanks Crow! I think the external loudness was the culprit. Still needs calibration but already sounds pretty good and seems like most everything may be working.

[Pioneers]

[Pioneers]

[medbot]

Nice, now there are two finished Crowminis in DFW! And people say Austin is the place for synths in Texas. Yours looks a whole lot nicer inside and out than mine does though

[Allen Huang]

Hi, Mr. Rider. This is Allen from Taiwan.
I ordered two crowminius bare boards two weeks ago. Order number 1332. It has not arrived yet and I hope that you can give me the tracking info. Thank you.

[Pioneers]

[mrmrshoes]

Hello all

I bought a PCB for this project about 8 months ago so its time to start getting down to building this up. I've been reading though the posts here and have a couple of questions.

I'm planning on doing a off board wiring build with a moog style panel. I've been messing about with oberling panel design , I'm planning on getting a acrylic laser cut panel done with the fancy rocker switches. (i can't afford the nice milled panel)

I've separated out the engraving layer and the cut-out layer in inkscape, I replaced the standoff holes with M3 holes for the switches. It looks like the switches will need an under panel to mount them properly, that shouldn't be to hard to add to the design.

Can anyone share their experience with sourcing the "KND2 2X2" from Daier via alibaba.com.

It looks like you have to buy 50 - 100 pieces at $0.16 each.

Are they any hidden charges when dealing with them? Whats the build quality like?

It would be nice to use these in the finished thing, But if its a pain i might switch to standard toggles.

Also can anyone tell me how the screen will function in the midi build of the crowminus? Can you set parameters with it?

I got 1.1.2 version of the pcb so i'm planning on building up the second dac for midi Mod and Pitch bend on a piece of strip board. Been looking over the schematic shouldn't to hard to pull off. Then i'll just flash the 1.1.3 firmware.

I'm planning on using this synth with the Arturia keystep keyboard with its midi output. I've got a MFOS soundlab Mark2 that will use the CV gate outputs. So hooking up the crowminus for midi control makes sense.

For headers to off board components i'll also use strip-board, So the rotary switches and 2mm headers switches will be soldered to a piece of strip-board with standard 0.1 headers attached. Saves time looking for weird parts. I can write on the strip-board with permanent maker so hopfully it will make troubleshooting easier.

I'll probs make a build thread once I get this under way.

[oberling]

[mrmrshoes]

cheers for the info on the switches man I'm pm'ing you now.

I'll post more here when I get things rolling along.

[crustibooga]

Just received my rev 1.1.3 board via the Kickstarter campaign. Thank you Scott!

[mrmrshoes]

I guess this is a question for Crow. I'm doing prep work for my V1.1.2 PCB build. I want to use the Dac based midi Pitchbend and mod. I've drawen a schematic for the piggyback DAC. Does this look right to you?

I've also done a PCB so if anyone wants just let me know. The PCB is pretty Rough at the minute, I'll smarten it up
The eagle files will be posted here once its finished.

[oldcrow]

That looks like it should work. Just make sure your DAC and the onboard one use their own CS lines. --Crow

[Allen Huang]

Mr. Crow,
I got the Crowminius boards. I was anxious about them and now I feel the wait totally worth. The quality of the board is awesome.

BTW, will you produce more microcontrollers for it? I think i'll finally need one.

[p4rancesc0]

Hi everybody,
sorry to bother but C22,C51 seems to be hard to find:

0.033 uF 50V radial film capacitor, in particular, ECQ-V1H333JL, is obsolete.

I'd like to know if this one:

Nichicon QYX1H333JTP
493-3461-ND
QYX1H333JTP

will do the job.

It's Polyester instead of "Polyester, Metallized - Stacked"

Any advices ?

BR

[mrgazak]

Hi

[sk23]

Hi guys,
I've a working 1.1 Crowminius that came with the Crow's pre-programmed MIDI MCU, firmware spring\summer 2015.

At the time the pitch bend wasn't implemented in the firmware.
Now I'm asking myself, if there is a new firmware version and what's new.

Thank you

[jimfowler]

Can anybody tell me why this would NOT work to power a trio of boards (MiniMoog 3D!!!): http://www.mouser.com/Search/ProductDetail.aspx?R=166LA12virtualkey546 00000virtualkey546-166LA12

Thanks.

- jim

[beedogs]

My kit showed up today. The panel looks really nice, but there's a bit of an issue:

The 1000 uF caps for the power supply are far too tall for the panel. They're over an inch tall each, and the pots and LEDs and other bits on the board don't have that sort of height; they'll never reach the holes they're meant to poke through.

Any recommendations on what to do? I'm thinking a lot of people are going to have this issue during their builds.

[mrgazak]

Hi beedogs

[kx173]

Just received the panel and PCB for the desktop version.

Here's what I paid for on kickstarter:

"The DIY Crowminius with front panel! This is a bare "through-hole" circuit board and build documentation for those who wish to scratch-build their own unit. Includes engraved 8.5"x11" front panel. "

I can find the BOM but nothing I could call "build documentation".
Is there a centralplace where all problems are listed so I don't have to scroll thru 36 pages of discussion spreaded in everey direction?
Nothing on the CS80 page unless I overlooked....

I was expecting some explanations about the dual input PS, Atmega, calibration etc..

[JanneI]

I'm told that silkscreen for 1.1.3 is correct, but I have also checked every component with the 1.1.3 schematic. No mystery values/components so far, but there is no noobie-style build documentation available that I know of. The Bom is mainly for 1.1.1, 1.1.2 & 1.1.3 changes listed at the bottom.

[beedogs]

The 1000uF caps are about 2.7cm tall, just over an inch. Most of the pots are much shorter than this. I'm guessing anyone wishing to use the supplied panel from the KS run will need to mount each pot and switch to it and run wires back to the board. This is fine but hopefully the build guide will offer some tips or suggestions which haven't occurred to me yet.

That being said, there is no build guide available yet (that I can find) but the part values are all silkscreened on the PCB, so mounting most of the bits and pieces should be pretty straightforward.

[mrgazak]

All V1.1.3 builders

A quick look at the datasheets for the rotary and switches suggests that, with the switches fitted flush to the PCB, the distance to the top of the threaded bush on each switch is as follows:

Toggle (e.g. Digikey EG2447-ND) 14.75mm
Rotary (e.g. Mouser 105-SR2512F-26NS) 18.5mm
The LEDs should have at least 25mm leads.

The pins on the toggle switch are only 3.3mm long so, realistically, the top of the bush on the switch can't be more than 16.35mm above the PCB if they are soldered directly into the PCB (my preference).

As I understand, it should be possible to use the front panel with everything soldered directly to the PCB and the switch bushes protruding into their holes but not fixed with nuts.

Therefore the toggle switch levers must not foul on their holes when the bush is not engaged in the hole. It seems like that might work up to about 2-2.5mm above the top of the bush assuming the hole is a normal fit for the bush. I don't know how thick the front panel is but I'm guessing it must be around 2mm to be sufficiently rigid.

So, all in all, it looks possible to build in this way if the tallest parts on the board are less than about 16.5mm. So far the 1000uF capacitors (C60, C61) are an identified problem. The Panasonic part, EEUHD1E102, (Digikey P15144-ND) is advertised at 16mm but only 25V. Should be OK, I think.

What else might be taller than 16mm?

Looking forward to testing this in reality when my PCB and front panel arrive any day now...

Gareth

[oldcrow]

I put them on the bottom. The smaller cap I leave on top at a right angle. I am working to finish up the build docs. --Crow

[beedogs]

Cheers for that. I kind of figured they might end up on the bottom of the board. Makes sense.

[kx173]

[hreggi89]

Hei Crow. Did you ever get around doing BOMs at Digikey and Mouser? I've got the v1.1 PCB and I did find the Digikey BOM another user here already made so I am mainly wondering about the Mouser one.

[oldcrow]

This is one of the (many) things I am trying to squeeze in there among these Crowminius builds. My mostly-DIY Crowminius Euro board sets arrived today, so that is an added incentive to get 'em done.

[JanneI]

Little heads-up for the 1.1.3 builders: I ordered the 1.1.1 BOM digi-key cart and found out that it's not complete for 1.1.3. So check the area next to cv/gate inputs jacks.. few resistors and capacitors missing from the 1.1.1 bom, 33nF etc..

[oldcrow]

I have a number of extra panels for the v1.1.3 board now available:

http://cs80-com.myshopify.com/products/front-panel-for-crowminius-v1-1 -3

I will have a panel for the v1.1/v1.1.2 sometime in December as I have a 3D printer now to test switch cap prints until I get one I like.

Happy Turkeyday Weekend,

Crow
/**/

[p4rancesc0]

has anyone ever tryed to buy this one ?

http://www.ebay.com/itm/1x-CA3046-DIP-14-OBSOLETE-Transistor-Array-NPN -60V-2-5A-1-7V-LM3046-ULN2046-/122041351438?hash=item1c6a3b3d0e:g:KV0A AMXQBg5RwrDL

I live in italy, not that easy to source.

Any hints ?

BR

[aquatarkus]

Might try to see if these guys ship there:

http://www.jameco.com/z/CA3046N-Major-Brands-Ic-Ca3046N-Lm3046N-Dip-14 -Gp-Npn-Transistor-Array_12079.html

[p4rancesc0]

thanks, more ore less it will cost the same with shipping to italy

[clofstedt]

anybody know how I can get a hold of a pre programmed midi Atmega chip? I am lost

[oldcrow]

I am going to stock more this weekend. --Crow

[beedogs]

Has the value of C119 changed in the 1.1.3 revision? Looks like it's a .47 uF film cap -- that's an awfully large (dimensionally) cap, it seems to crowd out the IC and the transistors around it.

[lowell513mx]

Is anyone familiar with the Social Entropy Engine sequencer? Will the Gate & CV on the Engine work with the Crowminius?

"Precise 16-bit outputs with a true bipolar output swing from -3V to +7V make it possible to get the most out of your analog synthesizers.

Gates output a +10V signal, which is perfect for triggering some older machines."

[aquatarkus]

Check this out - I think this may answer your question...

[lowell513mx]

[fomtoberheim]

Hey if i wanted to build this with an internal power transformer and an iec cable. Would i be able to find a transformer that supplies power to both inputs on the "Power supply that does not suck". J19 J18 J17?

[Le_paulf]

Looking b25k, a50k potentiometers with a D shaft.

Anybody know where I can find them?

[jimfowler]

[jimfowler]

I don't plan on incorporating the pitch wheel...should I jump the potentiometer solder points, find a resistor that's the median value of the pot that would normally go there or just omit the pot entirely?

Thanks.

[beedogs]

Having MAJOR problems with the note scaling on a 1.1.3 rev board. It seems to be affecting every oscillator, no matter what I set the zero/scale/octave trimmers to. The voltages look correct up to and including pin 1 on IC1, but here's what a C major "scale" (from C to B) sounds like:

http://bitey.net/crow2.m4a

This is with both OSC1 and OSC2 sounding at the same time. You can hear the pitches are roughly the same, but they're just way too far apart from one note to the next. (This can be replicated using both MIDI and CV control.)

I've double-checked all the resistor values in the pitch circuitry and everything seems spot on. Really not sure where the problem could be. Any ideas?

[beedogs]

Welp... I give up.

Nothing seems to be even close to in tune, no matter what I substitute for R4, and I'm getting a whole lot of crosstalk somewhere in the output stage. Any time the PWM LEDs light, there's a burst of low-frequency noise on all outputs.

Has anyone actually successfully built a rev 1.1.3 board?

[peAk]

[jimfowler]

So, finally got everything wired up and I have no sound. I haven't programmed the atmega chip yet, so I can't test the 440 tone and thereby check the vca.

My +/-10V are spot-on...however, where I'm supposed to have -5V I have upwards of -10V (except for pin 3 of IC2 - there I have exactly -5V). Specifically, at A6/C6 of the octave selectors I'm not getting the right amount of juice. At pin 7 of IC2 my voltages jump from 0 to -5.XX and on up to about -7.85 as I'm clicking through the range. I have -9.7V at all legs of Q1.

I'm good enough to bumble my way through tube gear but this shit is over my head. Any pointers would be most appreciated.

- Jim

EDIT - fried Q1...replaced it and we're now making progress.

[oldcrow]

Is this pitch CV from external input or from onboard DAC? Each one needs a different resistor value for R4. (100K for DAC, 121K for ext CV)

[beedogs]

[beedogs]

[blandoon]

Anyone using the bottom-mount Alpha switches (from Jameco) for the waveform and octave selectors: what are you using for knobs? Those are 6mm D-shaft, and I'm having a hard time finding anything that looks right and has the right fit.

[pokeyasd]

Hello oldcrow,

I would like to ask if at this point you're able to disclose the future of this project? I'm highly interested in building this and I'm thinking of purchasing a bare PCB, as they are in-stock now, but I probably won't have the time or resources to build it for a long time yet (months probably, years maybe). Therefore I'd like to know will this be available as DIY project still for some time and will there be improved versions? I'm under the impression that at some point there will be ready-made product for sale, but I don't know if it will replace the DIY product.

[peAk]

[sk23]

Hello,
I've a working Crowminius v1.1.
I would like to control via midi:
1) pitch bend
2) mod wheel
3) filter cutoff

With the actual firmware those control don't work via midi (I use the standard 4 pin DIN connector, no CV).

Someone can explain me please if it's possible to implement, and how, those functions.

Thank you

Regards

[oldcrow]

Make sure you are using a 12VAC wall-pak (or internal case transformer if that is the way you are going) that can supply 500mA. Lower current ratings will cause things to go all funny. --Crow

[ElSmurf]

[oldcrow]

To disable the pitch wheel, you want to "lock" a DC voltage into the pitch wheel node of the CV input summing amp. The easiest way is to just use a couple of 10K resistors where the pot would go, one from CW to center, and one from CCW to center. This places 5V on the pitchwheel node, which is needed to get other things into the correct default range. -Crow

[Pioneers]

I took a break on this project and now I'm back, trying to calibrate. It certainly seems rather involved.

[sk23]

Hi guys, I'm sorry to insist, but anyone could hep me?
thanks

[ElSmurf]

Perfect, thanks! That was the last puzzle piece for me.

[Pioneers]

I'm curious if this sounds like the correct way to calibrate:

Set Range to 16
hold low A and adjust the zero trimmer
hold high A and adjust scale trimmer
(repeat for all oscillators)

Set Range to 2
Hold low A and adjust zero trimmer.
Hold high A and adjust comp trimmer.
(repeat for all oscillators and also repeat above)

I feel like every time I try this I keep messing up the previous settings and seem to be just going back and forth from in tune to out of tune.

[ElSmurf]

I tested the power supply yesterday and I get a good +/-10V. Tried to start the calibration process today, but it appears OSC1&3 are dead. OSC2 has sound and responds to range, freq and waveform changes, as well as the PWM.

Checked all switches and connections, and they look good. Swapped out the ICs between OSC1 and OSC2 one by one, which changed nothing. The only big difference I measured between corresponding ICs on all three OSCs is pin 1 of the LM393Ns (IC8,13,18). On OSC2 I get a steady -5.3V, on the other two I either get 0V or -9.9V. It just jumps from 0 to -9.9 on the two dead OSCs - for no apparent or audible reason.


Any ideas what this could be, before I start checking all values and solder joints?


*edit* Just scoped the oscillators and I find no waveforms on the OSC1&3 ICs. When I touch pin 1 of IC5 and IC12 with the positive probe of my DMM, OSC1 resp. OSC3 produce sound, and respond to the waveform switch, but not the range or frequency controls. OSC1 responds to PWM also. I'm getting closer!

[oberling]

Hi sk23,

as far as i understand the source code the filter mod is already implemented (lines 308-312). It uses the second DAC-channel (first for Pitch CV) and you must set switch#1 to low and switch#2 to high for it to work on CC#11. If switch #1 and #2 are low it will respond to Velocity (lines 265-266). If switch #1 is high it responds to aftertouch (lines 315-318). So Filter modulation should be covered already.

The Mod Wheel is implemented as a PWM-DAC already as well (lines 302-306). For that to work you'll need to have the vactrol circuitry installed.

PitchBend might be implemented in software but will be not as smooth (if usable at all) opposed to using a dedicated DAC as in v1.1.3.

oldcrow implemented both ModWheel and PitchBend using a dedicated second DAC and some OpAmps for v1.1.3 so basically we (with older revisions) would only have to have some additional PCB to implement these things, wire it up correctly to our PCB (flying wires alert) and use a corrected version of the firmware - which seems not to be available as of now. However implementation should be straight forward.
The effort to design such an additional PCB has already been undertaken by mrmrshoes some posts back by just straight forwardly exporting the necessary differences between schematics v1.1.0 and v1.1.3 onto a new PCB.
This is not yet in production and currently lacks a 5.1k resistor... we'll see how that works out...

tldr: mrmrshoes and I are also on it... but it'll take time

[sk23]

Hi Oberlin,
thank you very much for your reply.

Everything is clear now.
Please guys keep us updated!

Cheers

[jimfowler]

For anybody who hasn't already populated their boards, do yourself a HUGE favor and use multi-turn trimmers...especially for the oscillator tuning section.

I'm sure this has been mentioned before but it bears repeating in my opinion.

[ElSmurf]

If anyone has an idea where to start looking, any help would be greatly appreciated. Transistors have correct orientation, btw.

[SynthOSphere]

[ElSmurf]

[Pioneers]

I agree about the multi-turns. I wish I had used them now that I'm trying to calibrate. I'm thinking it will be difficult to get the single turns out now.

[ElSmurf]

Finally figured out the problem yesterday. I doubt anyone will encounter the same issue, but I'll share for historic purposes.

When I first started to populate the board, I solder the through-hole tempcos flat on the board. When I figured out they needed to touch the 3046s, it seems I had some desoldering rage, and fried the traces between the tempco and pin2 of the 3046 for VCO 1&3. Two tiny copper wires between the tempco leg and the SMD pad later, and the synth worked like a charm.


Today I sorted out some wiring mistakes between the front panel and the board, and looks like I'm all set to start calibrating tomorrow. I'm also planning on writing down the tuning procedure, based on the text file provided by medbot earlier in the thread.

[ElSmurf]

Two questions :

1. I can't seem to get enough base voltage to tune OSC2, I run out of turns on the ZERO trimmer to get it up high enough to be in tune with the other two oscillators, with the OSC2 FREQ pot in the middle. I got it to scale across all octaves, but the Frequency knob is set to about +1 (30° past center) on the front panel. Would lowering the value for R53 help?

2. When I compare the waveform on the volume pots to the one I get from the main outputs, the final waveforms look very rounded. Is this normal behavior? Frequency knob is FCW, emphasis and contour FCCW.

[hreggi89]

Things seem a bit quiet here lately so I don't expect much help, but I'm still gonna post this for the off-shot that someone here reads this and can help me.

I've finally finished assembly but I don't get any sound from the synth itself. I get the test-tone on all outputs, all LEDs seem to work (except phase and tx even though I send MIDI signal to it, also tried changing phase jumpers. are they supposed to light up?) and the Gate LED lights up when I send signal from an outside source. I'm thinking the problem might exist in the filter or amplifier section because I get no signal from any of the oscillators, noise source or external audio in. If this is the case, where should I continue troubleshooting?

I have other things to do for the next couple of days so I won't be able to look into the problem much myself, if I get any headway I'll post here immediately.

[ElSmurf]

[hreggi89]

[ElSmurf]

How are you powering the synth? Looks like getting a good +/-10V should be your highest priority now.

Also, SW8 and SW10 require a DPDT switch, you can use SP for all the other switches.

[evengravy]

Hi, Just getting around to populating the TH 1.1(?) version.

I've no need for the MIDI functionality at all, I have plenty of options for sequencing with CV and want set it up for 1V/Oct CV input only.

Are the parts that can be left off the PCB in this case (MIDI DAC Parts) listed somewhere? The MCU and DAC are pretty obvious but resistors etc. I'm not sure.

I can always populate them and trim for 1V/Oct I suppose but I'd rather drop a Teensy MIDI/CV board in here down the line and save the space for it.

Thanks a lot!

[ElSmurf]

[sonicblue99]

Almost finished with a v1.1 board. Just waiting on the rotary switches. Besides the jameco ones, has anyone found another source?

[JanneI]

Hi, v.1.3 board -user here. I've done external wiring and first test wasn't fully successful. I'll check my wiring for errors.

Firstly, I only got the atmega generated 440hz from the main output and it's really quiet. Then I checked the oscillators with oscilloscope from the waveform switch common pin and all seems to be well except:
-all the tuning pots (tune/pitch wheel/detune (osc2-3) have a huge scale.
-octave switches don't work correctly, only with fully right I get a sound, otherwise silence.
-the output volume is really low. What kind of peak-to-peak voltages should I expect?

If someone has ideas where to look for error, besides wiring, please help, thanks!

Best,
Janne

[ElSmurf]

sonicblue99, I used these from Mouser. They are solder lug but they have pin versions as well.
http://www.mouser.be/Search/ProductDetail.aspx?R=SR2511F-0206-19R0B-E9 -N-W-159virtualkey14860000virtualkey105-SR2511F-26RN

JanneI - do you have a clean +/-10V from the PSU?

[poser1]

Hi there, I recently ordered one of the Q2 v1.1.3 boards. I've been reading up and studying the schematics in anticipation of the build. One thing I've been wondering is whether it's possible to use MIDI velocity as one of the controls for the VCA... from what I understand the Crowminius is set up for MIDI velocity to modulate the VCF. Could one not simply connect a wire from pin 6 of IC19 (filter CV from the DAC) and route that to the "loudness" jack or to the base of T21, in order to achieve some form of velocity control of loudness? I've searched the forum but haven't been able to find an answer. Thanks!

[Godric]

For what it's worth here is a pic of my crowminius build - a bit of a pig's ear but there we are.

[/img]

[p4rancesc0]

[johnnyquest]

Yes, I second that question and agree a very nice build! Good Job!

[Troubleshooter]

Hi all, ordered a bare board last week. Looking forward building it.

Planning to do an as good as possible scale replica (woodwork, panel, keys, left hand). I have a real D for measuring up things. I hope the board will fit it there somewhere (maby underneath the keys). I have a hobby cnc for engraving, milling the plastic mod wheels and so on.

I hate to solder wires directly on the board so I am allready looking for a connector to mimmic the slide switches. 2mm standard 2x3 connectors are out there but the switches seem to be a mix of 2mm and 2,5mm. Any suggestions? Maby I have to go for a seperate pair of 1x3.

Also a 44 keybed will be a challenge...Anyone experience with cutting down a larger keybed?

[Godric]

A very well-known (almost ubiquitous) digital synth from the early 80s donated the wheels for my Crowminius build.

While we are on the subject I am a bit puzzled by the spec for the modulation wheel VR16.

The BOM says '50k linear taper' however the digikey part number referenced is actually for a log taper pot. The PCB overlay say B5k, which is different again, a 5k linear.

Anyone built this section already? What works/is correct?

Regards

Godric

[Godric]

[Troubleshooter]

HI, still waiting for the board to get shipped, didn't receive any update since I ordered 2 weeks ago. Iguess the old crow is a busy man. In the meanwhile I vectorized an original frontpanel layout that I will engrave on me hobby cnc.
Since I never found any good Moog font in vector format I will compromize into something diffrent. Never mind the colors thats just for multiple layering.



I still have to change it for the extra bells and whistles found on the crowminius. Any sugestions on the location for the PWM's without changing the total size? I can use the layout from the reissue for the modulation switches (LFO and VCFEG).

[Troubleshooter]

This is what I got so far:

[Troubleshooter]

A question, some half of the crowminius fronts I have seen have the reverse saw on OSC3 the other half have the 3 times the same saw/tri mixed waveform. Wich one should I engrave for the rev.3 board?

[oldcrow]

Hi, I am awaiting delivery of the boards which were delayed three weeks from the board house. I will be sending out a notice for boards currently on order.

To answer this question this was me forgetting to change the panel graphic to the reverse saw on osc3. This is only on a few of my early panels.

Crow
/**/

[Troubleshooter]

Finished the faceplate and measured and milled out some mod wheels

[Godric]

[Troubleshooter]

[Troubleshooter]

Left hand controller taking shape.

[Godric]

I think I'll call it the coffin, as that's what it looks like from the side:

[JanneI]

Help needed troubleshooting my crowminius build.

Oscillators work, but no sound after the mix bus. I get all the waveforms from all the oscillators, PW&PWM works. Octave switches have -5v at "2, -4,5v at 4" etc, but after the cv-summer scaling is way off. Pitch wheel has to be more at the +10v end to get the oscillators audible rate and then octave switch at only 4" will drop the pitch under the audible rate. I still see oscillation happening on the scope..

I put jumpers (T-TS) at J2, J3, J13, J14 (jacks not mounted). Midi/usb not yet mounted. I get the proper +-10v, phase led ok. I get a quiet 440hz from the main output, so atmega should work? VCA makes a click sound when triggered (VCA offset I guess), so env's and VCA should work?

It still could be my wiring, but I did take time building and double checked everything. I now even tested it with only the neccessary switches and pots for osc1 and the it behaved the same way.

Could someone point me to the right direction? Proper voltages? Crow's schematic page3 is a little bit over my league, so it's hard trying to isolate things to make sure whats ok and whats not.. And why I'm not getting anything through on the main output?

Thanks!

[oldcrow]

Make sure you have the switch lug of the external loudness jack taken to +10V through a 33K resistor. The VCA will be off otherwise. --Crow

[JanneI]

Thanks, that jumper (loudness jack) gives me +7,7V, so it should be ok, right?

I get a really quiet 440Hz (from the ATMEGA) from hi output and phones and either of the VCA balance trimmers don't have any effect, should they? How could I first make sure that the VCA works?

[JanneI]

I have approx 3v peak-to-peak from the oscillator out switch pin2, this should be ok?

R177 - C22 junction is the vca input, right? Could I insert the osc output directly there (disable the filter completely)?

[p4rancesc0]

Wow, the panel looks amazing!

Where did you get the mod and pitch wheels ?
Are you going to share the project files ?

Thanks
BR

[JanneI]

I think my problem is the VCA, because I do get a proper sound out of the filter after the R177. 440hz can be heard very very quietly but nothing else comes through the VCA. I soldered a jumper to loudness jack (J2), switch to tip. I checked the transistors for mixing npn pnp, but they are all correct. Any idea how to solve this? Voltages to measure?

[JanneI]

Some progress. I grounded the S-trig and got the envelopes working, yay! So VCF&VCA are ok. Gate from the midi in started triggering the envelopes after I soldered the tx led. J2, J3, J12, J13, J14, J16 jumper from the T to TN (no jacks).

Still, CV from the midi is totally out of control. IC25 pin 5 (LF398, 6A_KBD) gives me reasonable good voltages when playing the midi keyboard, but oscillators go way, way off, on the limits of the hearing area. Octave switches make the -5v with 0,5v steps on IC2B pin7, pin8, pin14, but oscillators make hearable sound only at 2feet, highest octave setting on all oscillators. Pitch wheel and tune have a way too wide range (from LFO area to "not hearing anything anymore").

I guess i tried to be too clever with the "I can leave that unsoldered for now". Anyway, progress happening even thought not quiet there yet...

[JanneI]

After reading this whole thread, I measured the R24A, R64A, R102A, just to be sure, and found out that osc1 did give me a proper 1k ohms but the osc2 and osc3 gave 100k So I guess that needs to be fixed tomorrow. Hopefully this will make things all good.

[JanneI]

Tempco's fixed now, but one more thing still remains.

I'm using midi, R4 is 102k, but still playing just 2 octaves gives me "LFO clicks -> "so high that I'm not hearing anything anymore"-area". R4 gives me voltage steps that I consider to be correct. Octave switches have way too large scale, only switching to one step lower makes oscillator go to LFO area, even though I get -5V (and 0,5V steps) from the LM348 (7,8,14 pins). Pitch wheel is set to middle, +5V. Scale trimmers R16,R55,R91 works in a way that both ends (low and high keys) move to higher or lower, which I found a little strange...shouldn't this make lows go lower and highs go higher?


here's a video:
https://www.youtube.com/watch?v=7zP4VESYIh8

[Troubleshooter]

Getting there slowly. Board on the way, fingers crossed for import taxes




Gonne mount the crowminius board underneeth the keybed upsidedown and clamp the cables into the right bending angle towards the rotating knob surface.

[p4rancesc0]

Hi,
sorry to bother but is there any chance to get in Europe (Italy) this opto coupler ?

PC900V0NSZXF

Even a replacement would be fine if there's any...

Thx

[Troubleshooter]

[colorbars]

For anyone who's interested I'm selling my crowminius from the first run of boards here for roughly what it cost me to build...

https://www.muffwiggler.com/forum/viewtopic.php?t=187530

Hope it's ok to post this here, if not please delete

[Godric]

I carried this error forward onto my panel and didn't notice it until after fabrication - sigh!

[stringsthings]

I'm at the stage where I'm doing the mass of offboard wiring for my Crowminius build. I've got a question for the people who have finished their build ( or almost finished ). Did you need to use shielded wire for any of the offboard pots, switches, or jacks?

I can see the possiblility of shielding the wires to the outputs ( jack, pot, switch ). But if I don't have to shield, I won't bother. Doing all the pots and switches and jacks is enough of a headache.

[Troubleshooter]

I am about 50% done in wiring mine and took the risk to not shield anything. I will put my AC transformer in an external box however.
I never shielded anything in my DIY stuff except for a few cases (tube
guitar amps, backlit LCD displays close to audio chains, etc...). Since my cabeling is longer than usual also I don't really know what to expect. Fingers crossed.

[JanneI]

@oldcrow:

I'm back at troubleshooting my crowminius build. Still the cv from midi/tune/pitchwheel is way out of scale:

https://www.youtube.com/watch?v=7zP4VESYIh8

..so I was thinking could the problem be somewhere in the cv summers (IC1?), feedback resistor value perhaps?

What I have is (pcb1.1.3):

IC1A=TL072:
R1 = 301k
R2 = 100k
R390 =
R3 = 1M24
R4 = 102k
R5 = 100k
R6 = 121k
R7 = jumper

IC1B:
R13 = 69k8
R17 = 90k9
R19 = 53k6
R21 = 49k9
R22 = jumper
R23 = 2k32

R392 = 1k
R200 = what this should be?

If these are correct what should I try next? Thanks!

[stringsthings]

JanneI, what values did you use for resistors R23, R63, R101A?

These 3 resistors are related to the tempco resistors R24/R24A, R64/R64A, R102/R102A. If you got these mixed up, it might be the cause of your problem.

[JanneI]

Sorry, I edited the list above. So
R23 = 2k32
R24 = 1k tempco smd under the c3046.

Should my R23 be 23k2 with the 1k tempco?

[JanneI]

[stringsthings]

[wahee]

just wondering if there is a way to permanently set the MIDI channel on the Crowminius and OMNI off

[Troubleshooter]

I have made the first test run yesterday.

Adjusted PSU to -10,00 and +10,00

VCO's are working and tunable. However the range seems just out of reach of the trimmers. So I will have to change a resistor value. I also notice that my SAW wave is not symetrically (completely negative) and half of the amplitude of the TRI / TRAMP waves wich are symetrical. I have this in all 3 VCO's.

Noise is working

MIDI 2 CV/GATE is working

LFO LEDS are blinking

VCF/VCA seems to bee the problem child. The filter acts more like a LO-FI equalizer with limited range. It does affect the sound as a filter but doesn't have the required range (doesn't fully open or close) not by dialing the pot or contour or key track or trimming the range.
Emphasis is not working either. Moving the Emphasis knob or trimmer doesn't affect the sound at all. Also the main/headphone outputs are very very weak. The VCA however does close perfectly to silence. Balance 1 trim does reduce the "Click" sound.

Both VCA and VCF contours seem to work.

I havent tested any modulations yet.

I have built maby 20 DIY VCF's and never had one with limited range.
All tips for debugging filters are welcome since ladder filters are so hard to measure out.

All and all I am happy that it makes a sound from the first test.

[stringsthings]

[Troubleshooter]

[Troubleshooter]

[stringsthings]

[Troubleshooter]

Hi,

The LED is working as expected on both noise (flickering) and OSC3 (blinking).
R359 and pin 14 receive the modulation mix. Pin 16 should pull a negative current trough Q16 and R394. Any idea what currents to expect with mod wheel up and down (measurable by voltage drop over 394)?

Kind Regards,

Gerd

[stringsthings]

[peAk]

Good luck getting a Modulation pot that works well with this.

Moog used a special tapered pot that's pretty much impossible to find. That, coupled with the modulation bleed through, makes going from nice smooth tones to vibrato somewhat impossible. At least it was for me. Not so bad with filter modulation but more so with pitch.

I'd love to hear from Crow or anyone else that has achieved satisfactory results. I realize that many people are using just a pot and knob for the modulation control which is going to be more extreme cause of the full rotation as with the wheel that limits it somewhat

[stringsthings]

[medbot]

I agree. The modulation pot gives me about 5% useful travel and the rest is full blast. If I was doing it again I'd use a trimmer for the mod wheel, set it at max, and then have attenuator pots for VCO and VCF modulation instead of just on/off switches. That way I could easily set precise amounts for each (I hate them sharing the modulation level). Hell, if I was doing it again, I'd have separate modulation pots for each oscillator. And route the filter EG to the VCOs, and add sync, and, and, and.......

[Troubleshooter]

[Bassmanfox]

Hey just finished building this moog. Trying to either program an atmega328 or just buy one. Can anyone sell me a pre-programmed one?

I spent about 5+ hours here trying to program one using an arduino uno r3. software 1.0.6 using the setup/directions found here

https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard

First off I could not load the bootloader using my Mac Tower. It is running el capitan. Even After I check all connections and setting, it just never worked, but once I changed to a windows 8 machine it uploaded as expected. I'm 99% certain I got the bootloader loaded on to the atmega328p-pu.

Then I changed the wiring per the tutorial and tried to upload Crowminius MIDICV v2 to it.
I also added the dac/midi/adafruit libraries as described. but now I get a "midi was not declared in this scope error"
Crowminius_MIDICV_v2_release.ino: In function 'void setup()':
Crowminius_MIDICV_v2_release:232: error: 'MIDI' was not declared in this scope
Crowminius_MIDICV_v2_release.ino: In function 'void loop()':
Crowminius_MIDICV_v2_release:253: error: 'MIDI' was not declared in this scope

I tried everything I can think of, but arduinos are not my specialty. Might just have to grab a midi to cv converter for now, but it'd be rad to get the midi going. Let me know your thoughts or if you can just sell me one. Thanks!

[Troubleshooter]

You will need some sort of AVR programming device like the USBtniyISP for loading the bootloader. Then you need the right libraries installed in you arduino folder.

I just used the ARVDUDESS method as discribed on the CS80 crowminius page. This also requires a programmer.

Does anyone know a way to get velocity voltage out of the V113 board? I would like to mod the code and take the Bend Trim out since i have allready the Model D style pitch bend wheel. If I could send the velocity value to pin 8 of IC 26 instead of pitch bend I could connect it to a pot and jack like the model D reissue. I love velocity sensitive filter cutoff on a model D.

[JanneI]

I did some more digging on my crowminius build. Help would be appreciated.

Everything seems to work, except the output is extremely low on the high level output. I found out that all the oscillators work as should, but once connected to the filters 10uF cap, the oscillator signal goes from normal few volts (peak-to-peak) to just a few millivolts (around -1v). If non of the on-off switches are connected to "AUDIOMIX" I have normal signal on scoop on both sides of the R201 (33k), but once I connect SW5 pins 2 and 1 scoop only shows slight movement around -1V. All the "AUDIOMIX" inputs work the same way.

I have done external wiring, but problem isn't with that, because I removed all the switches and it still works the same way. I have jumpers on loudness etc. A440 works, but is as quiet as the rest of the synth. I did notice that for osc1&2&3&noise I had used B50k pots instead of B25k, does this make a difference? Or should there be a sort on the filter section on the pcb?

Filter works, vcf cv summer (aftertouch, mod section, key tracking), trimmers for range/reso/vca1/vca2, envelopes work..

It's got to be somewhere ;-)

Thanks!

[JanneI]

I removed the R177 (between VCF and VCA) and took audio out of this point, it's normal level, so the low level output -problem has to be somewhere in the VCA, right?

[JanneI]

Vca is current controlled, right? Anyway to test separate sections? +10v & -10v points are ok. Loudness t->ts jumpered, (+7,3v). Vca trimmers have effect, env works. Only the output is low level, even the A440. What should I look for?

[JanneI]

Ok, I think I found the problem. R194&R195 should be 8.2ohm and I have 8k2. Oops

Yes, that was it! I didn't find 8.2ohm so I used 10ohm. Still much closer than 8k2

[ElSmurf]

[JanneI]

[mutronic]

Aside from the stand-alone components, does the eurorack BOM differ that much from the stand-alone BOM for the crowminius?

[Staticcharge]

[mutronic]

I didn't get a response to that question, but I figured out you have to do some excel wizardry and convert the csv files to make the BOMs they have posted on Modular Addict legible.

[Staticcharge]

[Staticcharge]

[evengravy]

Hey Crow. I'm (slowly) building my 1.12 board and have some matched TIS97 transistors that I'd like to use in the ladder filter section. Apart from the orientation which is reversed from the 2N3904s the capacitors seem to be the same. Am I correct in thinking that I'll have to swap out the three 150R resistors for 220R if using TIS97.

I'd like to get the filter as close as possible to the original and I have these transistors anyway so I'd like to use them,

Thanks a lot, John

edit: oh, it looks like they're 150R in the original too...I'll just pop these in reversed then, the curve tracer shows quite a difference in characteristics between the 2N3904 and TIS97

[ElSmurf]

Hoping someone still reads this thread, here's 3 issues I still have with my crowminius

1. All 3 square waves are asymmetrical, being 47-53%. All components surrounding the LM393Ns are correct. Is this normal? If not, what could be the issue?

2. The output signal looks very different on scope than the actual waveforms pre-filter, all are sloped and rounded. VCF and VCF Range trimmer are open. Is this normal behavior? If not, what could be the issue?

3. The Zero trimmer on OSC2 is maxed out but doesn't get the osc high enough for tuning with the osc2 tuning knob in the middle. I'm assuming lowering the value for R53 would remedy this, is this correct?

Thanks in advance!

[Troubleshooter]

Hi StaticCharge. Here it is.



It has a few extra bells and whissles like an extra LFO as found in the Moog Reissue. It also has a tune pot on the back for the fixed frequency of VCO3 so you if you switch of the keyboard following of VCO3 you don't have to disturb the bigger VCO3 tuning pot and you can simply play the "OSC 3 CONTROL" switch in a musical way...Velocyty is patchable in the back to whatever you whant and it has an attenuator on the back. I have also built in a distortion cirquit located in the external input (true bypassable) great for making the filter feedback trick a bit more interesting sounding. Sonicaly the synth matches the reissue perfectly. You have to match it by ear however not by sight. The range of the pots it a bit diffrent here and there.


-