Sonic Potions - Penrose Quantizer DIY Kit

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Radical Ans
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Post by Radical Ans » Mon Feb 20, 2017 8:24 am

Put mine together last night and am having some major issues. When I power it up it looks like the input is bouncing around all over the place (i.e. the red note LED is going up and down across the keys). I placed a scope at pin 1 of the MCP602 and saw the following trace when I had 0V patched to the input.

Image

Looks like some kind of digital signal. Any ideas?

Edit: I should also note that the microcontroller appears to be working fine. I was able to put it into firmware update mode and send the latest firmware to the chip fine. The button LEDs also turn on and off with no issues when pressed.

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Radical Ans
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Post by Radical Ans » Mon Feb 20, 2017 2:03 pm

HUZZAH!!!

After some troubleshooting it looks like it ended up being some bad solder joints on the MCP602 socket. Seems to be working as expected now. I just need to do some calibration.

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Post by needspeed » Mon Feb 20, 2017 10:31 pm

I finished mine on Sunday after noting I was missing one freeking resistor. So as expected mouser came through for me and I powered her up and she worked right off the bat.

Missing the resistor was a good thing, as I must have checked the board 5 times in great detail ensuring every part was in the right place and all the soldering was correct. I like it as a good basic quantizer so far.......Steve

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Michiel
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Penrose voltage offset

Post by Michiel » Sun Mar 19, 2017 6:09 am

Penrose has been difficult for a while now. It consistently shows an offset of ~1.3V at the output, compared with the input.

I check input and output voltages with the two channels of my O'Tool.
With all steps on the quantizer enabled the output voltage is 1.3V above the input. Really annoying...

I've done a fresh calibration, also checked the solder joints. My kit was bought direct from Sonic Potions about 2y-18m ago. Standard build - no changes to any of the resistors or caps.

Plenty of weird behaviour in this thread already, but haven't come across this particular problem. Any suggestions?

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Post by desolationjones » Mon Mar 20, 2017 9:45 am

Does anyone have the schematic for Penrose? I'm trying to figure out if the LEDs are bipolar type.

I've been pondering a firmware tweak to add ascending/descending function for note selection. It would depend on being able to drive the green and red LEDs simultaneously to achieve yellow. Functionality could be:

Single short press: add note [green] or remove note [off] (as in current design)
Long press: add note to play ascending only [yellow]
Double-tap: add note to descending only [yellow]


@zipzinc that is a really cool addition you've made. Thanks for sharing the design with us.

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Post by mskala » Mon Mar 20, 2017 9:55 am

The schematic is at http://www.sonic-potions.com/public/Pen ... ematic.pdf - linked from the assembly guide. The LEDs are the two-wire type, so you can't drive red and green simultaneously. However, you don't need to drive them simultaneously. Blinking between red and green at a rate of at least a few tens of Hertz is good enough for human eyes to perceive it as yellow.

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Post by Radical Ans » Mon Mar 20, 2017 9:59 am

Schematic can be found here: http://www.sonic-potions.com/public/Pen ... ematic.pdf

I know because I had the same 1.3V issue and had to google around for the schematic a bunch.

My issue seemed to be bad solder joints on the U2 chip socket. For some reason the solder didn't adhere very well to it when I first built the module. I'd try and reflow all the joints on that socket and maybe some of the resistors associated w/ the 2 opamps on that chip (R3, R4, R5 etc).

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Post by desolationjones » Mon Mar 20, 2017 11:18 am

Thanks! I'll look into blinking them instead. With that concept I could use PWM to have orange as a fourth color.
mskala wrote:The schematic is at http://www.sonic-potions.com/public/Pen ... ematic.pdf - linked from the assembly guide. The LEDs are the two-wire type, so you can't drive red and green simultaneously. However, you don't need to drive them simultaneously. Blinking between red and green at a rate of at least a few tens of Hertz is good enough for human eyes to perceive it as yellow.

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Post by kreiff » Mon Mar 20, 2017 2:31 pm

Fierball wrote: I ordered direct. Just received my (second) Penrose kit, and noticed that it came with an MCP4821 (12-bit), not the MCP4801 (8-bit).

Does that mean the new firmware uses the 12-bit DAC as standard? And more to the point, can I replace the MCP4801 (assuming I also upgrade firmware) on my old Penrose to make them the same?
trockendock wrote:Yup. Finished building mine tonight. Kit also came with the 4821 which threw me off a little.
Fierball & Trockendock - How is the performance with the 12bit DAC?

Fierball - Is there significantly better accuracy with the 12bit DAC over the 8 bit DAC in your original build with the new firmware?

I think I'll try updating mine with the new firmware and new DACs anyway - but wanted to hear people's opinions.

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Post by Michiel » Mon Mar 20, 2017 5:19 pm

Radical Ans wrote:Schematic can be found here: http://www.sonic-potions.com/public/Pen ... ematic.pdf

I know because I had the same 1.3V issue and had to google around for the schematic a bunch.

My issue seemed to be bad solder joints on the U2 chip socket. For some reason the solder didn't adhere very well to it when I first built the module. I'd try and reflow all the joints on that socket and maybe some of the resistors associated w/ the 2 opamps on that chip (R3, R4, R5 etc).
Thanks - solder joints on the chip sockets looked pretty good. Will try and reflow around U2... (may be a few weeks before I get round to it - will update).

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Post by Daisuk » Wed Mar 22, 2017 4:52 am

Arrrr, good fucking grief I've been sloppy when building this, have just spent close to three hours filing down the bloody holes for the buttons because I soldered them without the panel on (misaligning them), and now one of the legs of the atmega chip just breaks off. Fucking hell! :bang: Hopefully I can buy a new chip from Sonic Potions, as I have no fucking clue how to program those tiny things.

Could I potentially just get the code from Sonic Potions, get a new Atmega, and upload the code to the Atmega? And if so, how would you do that? Would something like the pickit2 work somehow, or what would you need to get the code from a computer to the chip?

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Post by Michiel » Fri Mar 24, 2017 7:16 am

Michiel wrote:
Radical Ans wrote:Schematic can be found here: http://www.sonic-potions.com/public/Pen ... ematic.pdf

I know because I had the same 1.3V issue and had to google around for the schematic a bunch.

My issue seemed to be bad solder joints on the U2 chip socket. For some reason the solder didn't adhere very well to it when I first built the module. I'd try and reflow all the joints on that socket and maybe some of the resistors associated w/ the 2 opamps on that chip (R3, R4, R5 etc).
Thanks - solder joints on the chip sockets looked pretty good. Will try and reflow around U2... (may be a few weeks before I get round to it - will update).
Hey Radical Ans - thanks for the tip. I didn't really have any suspect solder joints - but I decided to reflow most of the two PCBs anyway. End result is that it now seems to work as intended. No more offsets.

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Post by Radical Ans » Fri Mar 24, 2017 9:59 am

Michiel wrote:
Michiel wrote:
Radical Ans wrote:Schematic can be found here: http://www.sonic-potions.com/public/Pen ... ematic.pdf

I know because I had the same 1.3V issue and had to google around for the schematic a bunch.

My issue seemed to be bad solder joints on the U2 chip socket. For some reason the solder didn't adhere very well to it when I first built the module. I'd try and reflow all the joints on that socket and maybe some of the resistors associated w/ the 2 opamps on that chip (R3, R4, R5 etc).
Thanks - solder joints on the chip sockets looked pretty good. Will try and reflow around U2... (may be a few weeks before I get round to it - will update).
Hey Radical Ans - thanks for the tip. I didn't really have any suspect solder joints - but I decided to reflow most of the two PCBs anyway. End result is that it now seems to work as intended. No more offsets.
Glad to hear it! When I was troubleshooting everything seemed ok up until the output opamp so I figured it was something funky around that chip.

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Post by funkymogli » Sat Apr 22, 2017 9:37 am

Hi, im having a problem with my penrose, its very unprecise..
its calibrated so a two octave jump is perfectly in tune, but if i just jump one octave is strangely 30 ct off, also the e (-30 ct) and other notes are randomly off a little, but enough to be really audible and make the whole thing useless for me.
the incoming voltage and the oscillator are very presice, with 7 octaves perfect tuning.


what are your expieriences? is that normal? what can be wrong?
thanks

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Post by a773 » Sat Apr 22, 2017 11:07 am

The firmware only uses 8bits of the DAC, so I think it's just impressions in the DAC you're seeking.

Supposedly there's a new firmware in the works that uses the 12bits of the DAC supplied with newer kits and implements a calibration procedure. Things should be much better with this in place.

Might not help much right now, I know...

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Post by Triglav » Sat Apr 22, 2017 12:20 pm

atte wrote:Supposedly there's a new firmware in the works that uses the 12bits of the DAC supplied with newer kits and implements a calibration procedure. Things should be much better with this in place.
Do you have a source on that or is it just based on the fact that they've included the new DAC?

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Post by a773 » Sat Apr 22, 2017 1:55 pm

Someone told me :hide:

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Post by Triglav » Sun Apr 23, 2017 5:34 am

Cool, looking forward to it! Hopefully it also fixes the bug where the UI sometimes freezes if I'm clocking the trig in at high speeds.

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Post by technicoloraudio » Sat May 13, 2017 3:41 am

just finished my penrose build and i was thrilled to see it light up when i plugged it in...

there is something going on with the buttons that is making them functionless. thye are all oriented properly on the board and i can start the module in firmware update mode and i did update the firmware, but bottom five white keys stay lit green and the top three black keys stay lit green with the exception of the top two keys alternating which is red.

i have checked every connection, polarity, and IC and everything seems to be in place.

anyone have any ideas?

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Post by Hezza11 » Tue May 30, 2017 2:27 pm

I was wondering if anyone else has had this problem. Every so often my penrose seems to freak out and do a really fast ratchet. Its kind of like it can't decided between two notes so plays both really fast.

Happens about 20 secs into the below video, its just a simple turing machine output, through the penrose making plinky plonky on a Rings.

I've had it happen with other random CV sources so its not the turing machine.

Any thoughts? It its actually quite nice some times but I wouldn't mind knowing what causes it, think it was another minute or so before it did it again.

(sorry for the vertical video!)
[video][/video]

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Post by eewee » Tue May 30, 2017 2:55 pm

Several people have noticed this as well, and if you look in the Sonic Potions forum, you'll find different solutions/workaround suggestions.

Here's one thread: http://forum.sonic-potions.com/discussi ... antization

At least make sure you're running the latest (1.2) firmware.
Why, say she now, is I not glean that one may say of thing while thing is not.
(Alan Moore, Voice of the Fire)

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Post by Hezza11 » Tue May 30, 2017 3:38 pm

eewee wrote: At least make sure you're running the latest (1.2) firmware.
Thanks for the heads up. Just updated (not sure what I was previous running) but the problem remains. Although I did read on that forum post about using the trigger input which seems to have stopped it.

Someone did post a link to a fix they'd made in the firmware but the link is dead.

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Post by a773 » Thu Jun 01, 2017 6:20 pm

A couple of weeks I spend a day with my four penroses, the 15 or so 8-bit dacs I ordered, my meter and a spredsheet. After a lot of measuring and swapping chips I now have all my penroses in tune in the range of +/- 3 cents with a few notes in the 7cents area. Super happy, huge improvement and totally worht the time spend.

It seems that some penroses were flat, some sharp, same with the dacs. So some that were like 20 cents sharp in one penrose made another penrose spot on.

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Post by lisa » Mon Jul 03, 2017 3:03 pm

I was looking for a quantizer that does exactly what I want and noting else and Penrose seems to fit the bill perfectly. A bit worrying though that so many of you have issues with it. :confused:
New track! Drum synthesis and melodies. ✨


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Post by a773 » Mon Jul 03, 2017 3:06 pm

If you solder it correctly, I think the main worry is tuning, which can be fixed by ordering 10 extra dacs and handpicking the best one...

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