MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

The Synthasystem Discussion and Appreciation Thread
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author The Synthasystem Discussion and Appreciation Thread
Isaiah
Welcome!

I thought a thread dedicated to discussing David Ingebretsen's resurrection on Nyle Steiner's Synthasystem would be a good resource and, I'm sure, an inspiration for anyone building or thinking about building a system or module based on these designs.

The Synthasystem, and the time and effort invested by both Nyle and David is more than deserving of its own topic.
Many, many thanks to Nyle and David for making this project possible!

Celebrate and discuss Synthasystem-based work here! Rockin' Banana!




SYNTHASYSTEM
PCBs and documentation available at David Ingebretsen's Analogue Realities site.


BLOGS
Dingebre's Analogue Realities
Diophantine's Synthasystem DIY


MODS

VCO - LINEAR FM
I spoke to Dr. Sketch-n-Etch a while ago about the possibility of implementing Linear FM on the Synthasystem VCOs.
Referring to the VCO A schematic:
Dr. Sketch-n-Etch wrote:
I'm not completely sure I understand the functioning of this oscillator completely, but I'm pretty sure that I know how to apply Linear FM.

Basically, you should try sending an attenuated signal through an 8.2k resistor in parallel with R14 into the common emitters of Q6. I believe that R14 sets the servo current into the VCO core, so modulating this current should give you Linear FM.

Give it a try and let me know how it works.


Asked if the Linear FM input would need to buffered:
Dr. Sketch-n-Etch wrote:
I think all of that is probably overkill. I think you could probably just bring the Lin FM modulation signal in directly through an attenuator and an input resistor. There is no servo amp in the circuit as it is, so why add a buffer? However, it's all "suck it and see" at this point -- whatever works!


THIS IS UNTESTED! Hopefully someone can test it. I will when I get around to my VCOs, but that may be a while yet.
A big thank you to Dave. I'm sure he won't mind me sharing his suggestion.


Triple EG - Linking Trigger Inputs
I'm using bananas in my system so I lose the convenience of switched jack connections (EG inputs chained 1>2>3).
If I want to trigger all the EGs at once, I have to use two cables to short all the inputs which is a bit boring.

I'm also using V-Trigs, but the S-Trigs inputs are available on the PCB.
By using switches to short between the EG's S-Trig inputs, you can replicate the OR gate functionality of the original Synthasystem, but with V-Trig inputs.

Taking that a step further: connecting EG1's S-Trig in via a switch to the anode of a diode, and the cathode to EG2's S-Trig in.
With the switch open, the two EGs function independently.
With the switch closed, a gate applied to Trig 1 in triggers only EG1, but a gate applied to Trig 2 in triggers EG1 and EG2.
Pretty cool!

Of course, the S-Trig inputs can be set up in any way you like.
I plan to simply label mine "Trig Link" as it's vague enough that I can swap the cables for the S-Trig connections to different headers and decide which envelopes are at the start of the chain.

This was kindly tested by David Ingebretsen himself. thumbs up
[/quote]
Rod Serling Fan Club
Good idea. There are various thread about the synthasystem on muffs. You might want to find them and add them as links to you first post.

I've got a few modules built in a euro/frac type format but have spent more time recently focusing on other builds. I think I might change them all and put them in a boat with bananas like my other stuff.

I am excited about the microcon PCBs. I'm seriously considering buying 4 and picking up that vermona midi to quad CV module to do a little 4 voice polysynth.
diophantine
I've started building a Synthasystem with banana-jacks. I'm documenting the whole project here:
http://synthasystemdiy.blogspot.com/



Finished a VC Trigger Generator, a Sample & Hold, and a Voltage Follower this past weekend, and should be finishing up 2 VCOs, a VCF, and a VCA in the next week. Hoping to eventually make it a 10U system.

So far, it seems to be a pretty neat system. I wanted something a bit smaller (but not too small) that would allow for faster & more improvised patching than my 5U. I also have been really wanting to build a complete system from only PCBs. The Synthasystem totally fit the bill! Looks great, sounds great (from the videos I've seen), and I like the limited - yet interesting - module selection: it has the basics (some with unique features), plus some more interesting modules. The sequencer has a great feature-set as well.

Props to Nyle for these great designs, and mega-thanks to David for making these available to the public + for all of his great help!
Isaiah
UPDATE:
I edited the opening post to include details of a really simple (but untested) mod for Linear FM that was suggested to me by Dr. Sketch-n-Etch. Thanks!
MechaSeb
Just ordered both faceplates from Schaeffer and PCBs from David. Still don't know if i build it in a banana format or like the original one, with tiny jacks.

Banana = would be awesome to interact with my Serge
Tiny jack = would be nice to start a syntha based eurorack

BTW here it's what i'm planning to build (for the moment) :

- VCO (x2)
- VCO Ba (x2)
- VCF (x2)
- VCA/Mixer (x2)
- Triple EG
- Noise
- Ring Mod
- Phaser
- S&H
- Voltage Processor/Mixer (x2)
- Voltage Follower
- Input Amplifier
- Peak Selector
- Sequencer

Can't wait to start building it. thumbs up
Isaiah
Congatulations, looking forward to seeing your system!
I've been watching Diophantine's blog with constant awe!

Not sure if you already know, but the TinyJax are not quite the same size as the 3.5mm standard that most Euro modules use. But I believe they are compatible...
I'm using some Kobiconn 3.5mm jacks.



I have two weeks of holiday from work starting this weekend.
Plan to have the following modules finished during this time:

*VCO A (at least one of the two)
*Noise
*Phaser
*Input Amplifier
*VCF
*VCA
*Triple EG
MechaSeb
Thanks for the kind words. I'm pretty exciting for having taken the plunge. I'm also following religiously Diophantine's blog by attending the birth of his first modules. Really informative blog btw.

Yes i know about the differences between commonly used eurorack 3.5mm jacks and Tiny ones. I also heard there is some cables which could work for both... therefore if i go fot tiny, DIY the cables would be a good idea too.

Isaiah wrote:


*VCO A (at least one of the two)
*Noise
*Phaser
*Input Amplifier
*VCF
*VCA
*Triple EG


Looking forward to seeing your modules too. thumbs up
Good luck with the build.
Rod Serling Fan Club
MechaSeb wrote:

Still don't know if i build it in a banana format or like the original one, with tiny jacks.



Ugh – me too. I can’t decide. I originally built them euro-sized with 3.5mm jacks. I got distracted with serge-esque builds. So then I was going to change all of my stuff to banana. However, I kind of miss the instant gratification of building a single module at a time and I like the idea of a small Steiner based 3.5mm system and I have a minbrute on order that I think would be a good controller/interface for such a system. I am so fickle with my DIY.
negativspace
I'm doing mine in unaltered Euro-format... that way I can keep them in my general racks until I have enough to populate their own 6 or 9U.

RSFC, I had the same discussion with myself about my DIY Serge panels - should I do them with 3.5mm jacks to integrate with the rest of my studio? I decided that it would be better to leave the Serge unintegrated - a limited (sort of) standalone instrument. Maybe the same principle applies in reverse to your situation?
Rod Serling Fan Club
Yes, I think that is probably where my mind is at after thinking on it for some time. I already have a large case built for “sorta-euro” DIY which has been neglected while I pursue the serge builds. That is where all my Steiner stuff is anyway. I will probably just continue building modules for that case. I can always add format jumblers for interfacing with bananas. It actually might be nice to take a break from building full boats and concentrate my efforts back on that project for a little while. While building a full boat of modules can be satisfying I tend to feel a little burnt out trying to wire/troubleshoot 10 or so separate modules at the same time.



@Isaiah and Dr Sketch – Thanks for the Linear FM mod info. I asked David about adding linear FM a while back but he wasn’t sure at the time. I’m hoping someone tries it before me but I do intend to give it a go.
MechaSeb
negativspace wrote:
RSFC, I had the same discussion with myself about my DIY Serge panels - should I do them with 3.5mm jacks to integrate with the rest of my studio? I decided that it would be better to leave the Serge unintegrated - a limited (sort of) standalone instrument. Maybe the same principle applies in reverse to your situation?


Same thing here. Finally decided to go Tiny ! thumbs up
The Serge is really powerful by itself and i'm not sure, even if the banana would help to interact with, to do it everyday. And i absolutely agree with your vision of the Serge as a standalone instrument. It makes total sens (at least for me). However, i gonna build a little Banana/Tiny adapter for those moments of interaction patching madness... w00t

By the way, gonna add those PCBs to my order :

- VCO a (third one)
- Frequency divider
- Selective inverter
- Triple EG (second one)
- VC trigger generator (x2)
and perhaps also another VCA (third one) and Sequencer (second one) .

Then i'll need a decade or so to build it Dead Banana Rockin' Banana!
Rod Serling Fan Club
Wow Mecha, that is going to be quite a system.

I think mine will be a mix of things, it already is. I think this system will be primarily Steiner with a lot of Ian fritz stuff as well.
I have these:
VCO
EGx3
VCA
VCF (synthasystem)
VCF (CGS synthacon)

I’d like to add a second VCO, phaser and microcon at a minimum to the Steiner stuff. I’m on the fence about the more basic stuff like ringmod, S&h, noise as I already have non-steiner PCBs for this stuff.
MechaSeb
Hi Rod,

IanFritz designs looks great too ! Looking forward your mix system.
About the CGS version of the VCF i heard that Yves from YuSynth is going to update his website soon with a bit of enhancement on the filter circuit (actually what he did on the Minibrute). It could be worth the wait.

Btw i designed faceplates for two new really basic modules i'm planning to add on my system.
I still need to arrange a bit the holes on the multiple (especially the space between) but for the moment here it is :

Mutliple & Power switch (inspired by the right bottom module which appear on the pic of the synthmuseum website's synthasystem) :



And a pretty simple Banana/Dual tiny jack adapter :



If you are interested building those i will share the .fpd when completely done. thumbs up
diophantine
Isaiah wrote:
I've been watching Diophantine's blog with constant awe!

MechaSeb wrote:
I'm also following religiously Diophantine's blog by attending the birth of his first modules. Really informative blog btw.

Thanks!! Glad you are enjoying! thumbs up

For those curious & not following along at home, here's the latest additions:




Hmm... looks like a police line-up. "Yes, officer, it was definitely #6 that was making all that racket last night!!!"

And, of course:


I've been a bit behind in progress lately... got assigned to jury duty for a 2 month trial(!), so that + commute + trying to do work when I get home leaves me a bit tired...

Really, I just need to build some power cables & mount stuff in my rack! But, everything I've played with sounds great.

I have also finished building a Triple EG - EGs 1 & 3 work great, but EG2 seems busted... I need to debug more, but I think it is a bad cap. Anyhow, it seems to be a really cool module!

I'm also hoping to order a Frequency Divider panel next week... I've got everything ready for it (except knobs!)

BTW, there's also a small issue with the UJTs that I've been discussing with David and which he's discussing with Nyle. Apparently they don't make 'em like they used to - or there's a very wide range of manufacturing tolerances. They're fine in the S&H (just a simple fixed oscillator), but in the VC Trigger Generator you can rarely get periods below ~8 seconds, and there's apparently problems in the Sequencer at fast rates, with certain UJTs. (I don't have the Sequencer, so I'm just writing off of memory here.) Just thought I'd throw that out there... best to use a socket or something on those two affected modules and try a few... that's what I'll do on future builds.

I'll post a few banana-comments in a few minutes... just need to gather my thoughts...
Rod Serling Fan Club
diophantine wrote:


I have also finished building a Triple EG - EGs 1 & 3 work great, but EG2 seems busted... I need to debug more, but I think it is a bad cap. Anyhow, it seems to be a really cool module!



Odd I have the same problem with mine. Please let me now what you find. I am curious to see how your 3eg panel w/bananas since there is some normalization.
diophantine
Ok, a few comments regarding bananas & interaction!

I've redesigned nearly all panels in FPE to allow for banana jacks with double D-holes, like the one pictured below. I tested them too by first placing a hole that corresponded with the panel dimensions of the jack, to make sure they wouldn't overlap. I'm using standard Emerson jacks. A couple had issues where I needed to grind one side of the standoff to make it fit, but I've since corrected the panels (though I haven't tested them).

In some cases I had to move the jacks so that they wouldn't overlap or be too close. In some other cases I moved them slightly for aesthetics (jacks were too close to the bottom, etc.) or I moved the jacks and/or the legends around them (particularly on the EG). On a few of these it has been a tight fit screwing on the nuts, but nothing really difficult or problematic.



Eventually I would like to make my FPD files available to the public, but before I do I want to (a) get permission from David, and (b) make sure they all work. I haven't done the Trigger Converter, since I am using S-Triggers, I have no need for it. I have done the two smaller VCOs, but I don't know if I will be implementing them. But, in the meantime, if you would like to see my FPD files, just shoot me a PM.

Of course, your mileage may vary depending upon what banana jacks you're using!

Also, regarding interaction with the Synthasystem and other synths, personally I am slightly wary of it. While I'm no EE and no expert on input/output buffers and impedance, a good deal of Synthasystem modules don't follow what has become the de facto standards for modular synths these days. (Not a surprise, considering it is a 35 year old design!) I don't know if this is a big deal, but I'm a fraidy-cat. (And, at least to me, it doesn't matter too much - I want my Synthasystem to be a self-contained system.) You may just want to run your ideas by David or someone more knowledgeable than myself.
diophantine
Rod Serling Fan Club wrote:
diophantine wrote:

I have also finished building a Triple EG - EGs 1 & 3 work great, but EG2 seems busted... I need to debug more, but I think it is a bad cap. Anyhow, it seems to be a really cool module!


Odd I have the same problem with mine. Please let me now what you find. I am curious to see how your 3eg panel w/bananas since there is some normalization.

Curiouser and curiouser... how does your EG2 behave? Mine just outputs a gate, as if Attack=0 & Decay=0. The level is affected by the Duration Level pot, but the Attack and Decay pots don't do anything (nor do any of the switches).

My EG panel looks the same as David's, but (1) I've removed the normalization & markers from the trigger input jacks, (2) I've spaced out the jacks a bit more horizontally, and (3) I've re-drawn the COMM arrows on the output jacks. I'll just stack bananas for the input.

Crap pic, but...
Isaiah
Diophantine
Excellent work!
Can't wait to see some photos of all your modules together.

Do you have a component number you could share for the little right-angle brackets used for mount the Phaser, Noise, Ring Mod etc. boards please?
I'm ordering components from Mouser and BanzaiMusic soon, so hopefully an equivalent can be found there.
Isaiah
Rod Serling Fan Club
I'll hopefully have one of my VCO As finished before ordering the front panel for it,
so I'll try the Linear FM mod and report my findings here.

I used David's FPD files (unaltered) for all my panels, but might modify the VCO A file so the Coarse Frequency control is centered and can accommodate a Davies 1913BW, while the Fine will be a Davies 1900 offset (like the Variable CV in relation to the Frequency control on the VCF).
If I decide to implement Linear FM, I'll see if it can be done using the existing Variable CV input and potentiometer with a switch to select Exp/Log and Lin.
Also, while I realise the Synthasystem standard seems to be attenuator at source, not destination, I'm debating whether to add an attenuator for the PWM input. Hmmm...
diophantine
Hey Isaiah, sure thing! The right-angle piece is Mouser #534-621.
Rod Serling Fan Club
diophantine wrote:
Rod Serling Fan Club wrote:
diophantine wrote:

I have also finished building a Triple EG - EGs 1 & 3 work great, but EG2 seems busted... I need to debug more, but I think it is a bad cap. Anyhow, it seems to be a really cool module!


Odd I have the same problem with mine. Please let me now what you find. I am curious to see how your 3eg panel w/bananas since there is some normalization.

Curiouser and curiouser... how does your EG2 behave? Mine just outputs a gate, as if Attack=0 & Decay=0. The level is affected by the Duration Level pot, but the Attack and Decay pots don't do anything (nor do any of the switches).



It's been a while since I played with it. That system isn't set up at the moment but I've started working on it again. I will let you know when I get back to it.
Rod Serling Fan Club
Isaiah wrote:


VCO - LINEAR FM
I spoke to Dr. Sketch-n-Etch a while ago about the possibility of implementing Linear FM on the Synthasystem VCOs.
Referring to the VCO A schematic:
Dr. Sketch-n-Etch wrote:
I'm not completely sure I understand the functioning of this oscillator completely, but I'm pretty sure that I know how to apply Linear FM.

Basically, you should try sending an attenuated signal through an 8.2k resistor in parallel with R14 into the common emitters of Q6. I believe that R14 sets the servo current into the VCO core, so modulating this current should give you Linear FM.

Give it a try and let me know how it works.




I got back to completing my VCO and thought I'd try the lin fm mod. Just to make sure I understand: Just solder another 8.2k from the input jack to the point on the PCB where R14 connects to the emitters of Q6?
Isaiah
Yes, connect to the junction where R14 joins the Emitters of Q6.
Could also try decoupling the input signal with a capacitor first too. AC/DC Lin FM.

I'd maybe connect a pot as a variable resistor in series with the 8.2K.
Though a variable potential divider might work too, I just have a feeling that the Lin FM input should be 'floating' like the Var. CV input on the VCO.

Very interested to hear how you get on with it!
Hope it works well!
Isaiah
RSFC
Did you have any joy with the Lin FM mod?
MechaSeb
Just received two of my big orders. One from David himself and the other from FPE. David is really professional and it's a pleasure to deal with. First time i receive something from FPE too but it blew my mind how the front panel are quality made. Really happy for the moment !

Wil post some ugly pics tomorrow just for fun.

Edit : here they are













Isaiah wrote:
RSFC
Did you have any joy with the Lin FM mod?


would like to know too thumbs up
Rod Serling Fan Club
MechaSeb wrote:


Isaiah wrote:
RSFC
Did you have any joy with the Lin FM mod?


would like to know too thumbs up


I added the mod but I haven't tried it yet. The module wired and ready to go but I am missing the trimmer for the high-freq tracking PCB. I might calibrate this weekend and install the hi-freq tracking later. I'll let you know.
Isaiah
MechaSeb wrote:
Just received two of my big orders. One from David himself and the other from FPE. David is really professional and it's a pleasure to deal with. First time i receive something from FPE too but it blew my mind how the front panel are quality made. Really happy for the moment !


Wowee zowee, congratulations!
That'll keep you busy for a while! eek!
I couldn't agree more about David, such a gentleman.
Isaiah
Rod Serling Fan Club wrote:
MechaSeb wrote:


Isaiah wrote:
RSFC
Did you have any joy with the Lin FM mod?


would like to know too thumbs up


I added the mod but I haven't tried it yet. The module wired and ready to go but I am missing the trimmer for the high-freq tracking PCB. I might calibrate this weekend and install the hi-freq tracking later. I'll let you know.


Exciting!
How did you decide to implement the mod?
e-grad
Any first hand experiences on the Triple EG?

How does it compare to function generators such as the Buchla 281?
diophantine
e-grad wrote:
Any first hand experiences on the Triple EG?

How does it compare to function generators such as the Buchla 281?


I actually just finished debugging the second EG earlier this afternoon (was a busted pad!). w00t I haven't played around with a whole lot, but a bit.

It is something of a hybrid between a traditional ADSR and a AD/AR, but with a number of extra & interesting features. Not sure if I'd compare it to a 281, but they do both allow AD and AR (though AR just on EG3), and you can combine envelopes.

Triple EG allows for more ADSR-style envelopes, but with less knob-fiddling than traditional ADSRs. It also allows a fixed sustain time on EG3, and delays on EGs 2 & 3. The damp & qtn functions also allow for the creation of interesting envelopes.

281 has the quadrature mode, CV attack/decay, repeat mode, and trigger output.

I think they're both interesting & worthwhile! I am considering building both into my MU modular, even.

It has been a while since I've seen it, but I seem to recall that in this video David did shows most all the features of the Triple EG:
e-grad
Thanks!

I've still some 281 in the pipeline and have finished one 281 which is a blast. At least for the kind of stuff I do.

However, the Triple EG seems to add some really unique features which would blend nicely with my system. ATM I must resist but guess I'll end up with one Triple EG.

Nice work, David! Thanks for making it available.
Rod Serling Fan Club
I wonder if there would be any interest in a group buy of MPC euro panels for the synthasystem? Right now my panels are etched but I wouldn't mind some professional panels if there was enough interest to make it feasible.

They would be the standard euro-silver (aluminum) color with black print. This is also how the earlier synthasystems looked.
Isaiah
RSFC
Sounds like a good idea!


I'll post photos of my panels soon.
I used David's FPD files and had them machined by thebeast.co.uk on natural aluminium with black in-fill.
They look very handsome!

I have an alternative VCO A panel that I made using David's as my starting point.
It's much more like the early, silver Synthasystems.
I'll check with David, but I'm sure he won't mind me posting it.
Isaiah
David announced the Duophonic Keyboard project here:

www.electro-music.com/forum/topic-52687.html

Rockin' Banana!
Rod Serling Fan Club
Isaiah wrote:
Rod Serling Fan Club wrote:
MechaSeb wrote:


Isaiah wrote:
RSFC
Did you have any joy with the Lin FM mod?


would like to know too thumbs up


I added the mod but I haven't tried it yet. The module wired and ready to go but I am missing the trimmer for the high-freq tracking PCB. I might calibrate this weekend and install the hi-freq tracking later. I'll let you know.


Exciting!
How did you decide to implement the mod?


I got started on trimming the VCO last night. I'm not done but I tried both FM inputs. I think the suggested resistor value is too high, it was FMing it through the linear mod but it was doing so as if it was very attenuated and there was no attenuation. exp FM and the oscillator in generaly sounds very nice so far.
negativspace
I really do love the VCO, David has it right that Nyle outdid himself with that design. Next to my Z3000 it's the one I go to most often and it never disappoints me. It tracks very well (even without the hi-freq tracking PCB, which I received after the fact and have not installed) and it always manages to sound alive no matter the waveform I use. The sawtooth cuts like a knife. I think I'll leave this one in my general Euro racks even when I pull the trigger on the standalone 9U I'm planning.

(I sent my case pattern off to my woodworker buddy a short while back so the wheels are finally turning... we bought some nice curly maple for it - exciting times!)
Isaiah
Rod Serling Fan Club wrote:

I got started on trimming the VCO last night. I'm not done but I tried both FM inputs. I think the suggested resistor value is too high, it was FMing it through the linear mod but it was doing so as if it was very attenuated and there was no attenuation. exp FM and the oscillator in generaly sounds very nice so far.



Glad to hear your VCO is working and the Lin FM mod works (to some degree).
How does the Lin FM sound?
Rod Serling Fan Club
very attenuated hihi

It’s hard to tell at that level. I need to finish adjusting trimmers and then get back to it. I might just try it without a resistor at all and work back from there.
Rod Serling Fan Club
double post
bleeps
I have some questions about the VCO-A. I'm looking for a solid DIY VCO for subtractive synthesis and I think this one will fit the bill. But, I want to slim down the panel or perhaps fit 2 or 3 behind a panel the same size as the traditional panel. Would I be missing out on any of the core features or patching potential if I did the following:
1) One output jack per waveform
2) Removed the waveform output attenuators
3) Reduced the number of CV inputs to one jack

I'm also curious about the Selective Inverter. That sounds like it could be fun to play with.
Isaiah
bleeps

Building a Dual VCO-A behind a 28HP panel is certainly possible.
I had considered doing it myself when planning a monosynth-style 3U Synthasystem, but have since decided on 6U.
(But now I'm thinking about a Dual VCO again...)

A Dual VCO would be a 3-layer PCB sandwich - VCO 1, VCO 2, two PSU.
Each VCO A PCB is 4.5" and each PSU PCB is 2.5", so you'd have to use slightly shorter or longer standoffs between VCO 2 and one of the PSU PCBs.

1 - Most VCOs only have a single output per waveform, so...

2 - If you're building a Synthasystem, I'd say the output attenuators are fairly important.
While omitting them wouldn't be a problem when using a VCF with input attenuators, most of the Synthasystem modules only have output, not input, attenuators.

3 - Two 1V/Oct inputs allows you to send a sequence to one input and transpose it with the other.
Of course you could use external modules to sum CVs externally.
Many VCOs only have one 1V/Oct input.
The VC3 input and its associated attenuator act as an Exp FM input.
bleeps
Thanks for the info. I'll go ahead and keep the inputs!
diophantine
Yeah, I agree with everything Isaiah has said. The multiple outputs & attenuators are only truly useful in a Synthasystem. Note that the VC3 attenuator isn't a true attenuator, but actually adjust the gain ratio of that input with respect to the 1V/Oct inputs. It is a great VCO!

Regarding the Selective Inverter, I just finished building mine last night. So it isn't in my blog yet, and I haven't done anything with it beyond a few simple tests. One nice thing about it is that it'll act as a mixer and voltage processor too. I'm very curious to try it out in a "real world" situation...
Rod Serling Fan Club
I tried the linear FM mod without a resistor tonight. The results were much better. From my basic tests so far it seems a bit unusual, almost like the way it was reacting to the frequency that was FMing it was backwards but it was very interesting and useful sounding regardless. I still need get the oscillator fully trimmed. I'm working on a few different things at once d'oh!
Isaiah
bleeps
No worries.
I might make a Dual VCO A panel using FPE.
If I do, I'll share the file.


Diophantine
Yes, you're correct - it's not a true attenuator.

The SI looks very interesting.
Certainly as unique as the Synthasystem "voice" modules and sequencer.
Interested in hearing your thoughts and opinions on using it.

RSFC
Glad to hear it's working now!
Do you mean the response to the CV is inverted (for example, a fixed positive voltage to the Lin FM input lowers the VCO frequency)?
I'm sure this could be solved using one of Ken Stone's DC Mixer PCBs set up as an inverting op-amp.
Using a pot in place of the feedback resistor would give you an attenuator.
And the PCB is small enough to be mounted like the HF Trimming PCB.
vegas7188
Hey all,
sorry i think this is probably a pretty newbie question, but i was thinking of diy'ing a couple of the simpler modules, was just wondering about the power regulation parts. on the schematics of each individual module it shows the power regulation circuits at the bottom, there is also a separate power regulation and filtering pcb listed.

I intend to be using the finished modules in a low-cost doepfer euro case, which provides +-12v, so do i need the power regulation sections on each schematic on each separate module i make, or is one of these for many modules enough? or do i even need one at all? considering i have the doepfer power supply (which i'm guessing is regulated?)

If i don't need the whole power regulation sections on the schematic, which parts of the power part on the schematic do i need?

Thanks very much,
David
Isaiah
Each module requires its own PSU PCB (or the on-board PSU filtering components).
It's not possible to share one PSU PCB between several modules.
But each module PCB set includes a PSU PCB anyway (or space for the PSU components on-board, in the case of the single-PCB modules).

Even if your Doepfer case provided the necessary +12/-10V, each module would still need the PSU PCB or on-board PSU filtering components, because some modules have extra filtering components (I believe they are labelled 'As Required' on the schematics & PCBs).

For use in a(n) Eurorack system you need all of the PSU filtering components, except the positive regulator and the associated components (these are identified in the schematic and on the PCBs).
The only modules I can think of that don't use -V, and thus require no negative filtering components at all, are the Noise Generator and the Triple EG.

If you read through all of the literature, it should be in there.
David's documentation of the modules is top notch.
Hope that helps!
vegas7188
Brilliant, thanks for the info Isaiah,

You're right all the documentation is great, i think i was just getting confused in my head about whether or not each module needed the psu bit!
Rod Serling Fan Club
Isaiah wrote:
RSFC
Glad to hear it's working now!
Do you mean the response to the CV is inverted (for example, a fixed positive voltage to the Lin FM input lowers the VCO frequency)?
I'm sure this could be solved using one of Ken Stone's DC Mixer PCBs set up as an inverting op-amp.
Using a pot in place of the feedback resistor would give you an attenuator.
And the PCB is small enough to be mounted like the HF Trimming PCB.


From my initial tests, the response did seem to be inverted.
Isaiah
No worries.
Which modules are you interested in?

Diophantine seems to be the Synthasystem Master around here, I'm sure he'll chime in if you're looking for opinions on certain modules.

I'm currently in the process of wiring my VCF, VCA and Triple EG.
Not the most fun I've ever had, I must admit...
Anyway, when they're finished I'll post photos and maybe a video.

David Ingebretson is a pleasure to deal with and true professional.
I, and many other folk, can't recommend the Synthasystem project enough thumbs up
bleeps
Isaiah
I saw your panels in the proofing thread (I didn't spot anything off btw), and I was wondering how important is the 1v/oct trimmer panel access? Does that need to be tweaked often?
Isaiah
bleeps
Thanks for looking at the panels!
Does the spacing look 'even' or 'balanced' to you?

I don't suppose the 1V/Oct trimmer is something that would need to be adjusted often. Apparently the tracking is stable.
I imagine it was kept on the front panel as much for aethetics as it was for practical reasons. The original Synthasystem VCOs and VCF had panel-mounted trimmers.
No harm in keeping them on the panel if you have the space.


By the way, I was trying out different panel layouts for a Dual VCO A (placing the knobs on a 28HP-sized piece of card).
You can actually fit all 8 output attenuators in a horizontal line (using Davies 1900 knobs, or some other ~12mm/0.5" diameter knobs), but I thought it looked kind of ugly/crowded/unbalanced.

I did think about a mono-synth (Minimoog or Synthacon) approach:
*Single individual outputs per waveform
*Two assignable outputs each with their own attenuators
*Each assignable output/attenuator fed by its own switch, one which selects Sine or Triangle, the other selecting Saw or Pulse.
It's not without its problems though, and I'm not completely sold on the idea.
Two attenuators seems a little clumsy.
One attenuator and a rotary switch to select waveform seems more elegant, certainly more mono-synth like, but uses up just as much panel space and it's more limited.
Of course, if we didn't need the output attenuators, it'd be much easier!
Rod Serling Fan Club
On the panel group buy I was going to propose dropping the trimmer, as it does seem a bit redundant to me. Then I would move the VC3 scale left, centered below the triangle attenuator so the knobs placement was completely balanced.

I am thinking about adding a linear FM input but seeing how I am the only one that has played with the mod so far I want to hear from others after they implement it. Anyone with a working VCO can test the LIN FM with an alligator clip connected to the end of R14 resistor going into the emitter of Q6. The other end of the clip connected to your FM source.

Personally I kind of like the big look of the larger panels and it makes wiring/diy a bit easier when you have more space to work with IMHO. If you are really looking for small panel/functional density, you could drop all the output attenuators, v/oct trim, the secondary outputs and even 1 or 2 of the inputs. Consider though, that the PCB is not small and you have 2 PCBs stacked per VCO (though you could probably get away with running 2 VCOs off of 1 power PCB).
synthcube
I posted a new topic called "Synthasystem Power Requirements Summary" with an attached PDF for a table I built, summarizing power needs for each module. Hope it is helpful.
Isaiah
RSFC

Yes, I like the look of the larger panels too.
Plenty of room to wiggle! Rockin' Banana!

The Dual VCO A isn't something I'm interested in build myself.
It'd be simple enough to design a layout for a general Euro system without the attenuators and some other things, like you say.
But to make it integrate best with a Synthasystem is bit of a challenge, and I'm not sure I can think of a satisfactory solution.

Ultimately, I'd I think I'd advise against a Dual VCO A for a Synthasystem, too.
I think I just have Dual VCOs on my mind at the moment (Dual 258J soon)!



I'll test the Lin FM mod, but I probably won't have my VCO running before the end of April.
Maybe Negativspace could be persuaded to test the mod hihi
What did you mean about the Lin FM signal having the opposite effect on pitch? Did you see my suggestion about using a CGS DC Mixer as an inverting amp to invert and attenuate the input?
Rod Serling Fan Club
I think it is inverted. Your idea sounds good to me, maybe there is a very simple inverting op-amp idea for perf board. I would like multiple opinions on the linear FM before implementing it on a panel for group-buy.
negativspace
An inverting opamp would help in 2 ways - first it'd fix the inversion, and second one could give it 2x gain (or more) for better depth of modulation. Such an addition is blindingly simple, just an IC and a couple of resistors.
bleeps
Isaiah wrote:
bleeps
Thanks for looking at the panels!
Does the spacing look 'even' or 'balanced' to you?

The spacing looks ok to me. I do agree with emdot about jacks above knobs though. I try to avoid that.

Quote:
I don't suppose the 1V/Oct trimmer is something that would need to be adjusted often. Apparently the tracking is stable.
I imagine it was kept on the front panel as much for aethetics as it was for practical reasons. The original Synthasystem VCOs and VCF had panel-mounted trimmers.
No harm in keeping them on the panel if you have the space.


By the way, I was trying out different panel layouts for a Dual VCO A (placing the knobs on a 28HP-sized piece of card).
You can actually fit all 8 output attenuators in a horizontal line (using Davies 1900 knobs, or some other ~12mm/0.5" diameter knobs), but I thought it looked kind of ugly/crowded/unbalanced.

I did think about a mono-synth (Minimoog or Synthacon) approach:
*Single individual outputs per waveform
*Two assignable outputs each with their own attenuators
*Each assignable output/attenuator fed by its own switch, one which selects Sine or Triangle, the other selecting Saw or Pulse.
It's not without its problems though, and I'm not completely sold on the idea.
Two attenuators seems a little clumsy.
One attenuator and a rotary switch to select waveform seems more elegant, certainly more mono-synth like, but uses up just as much panel space and it's more limited.
Of course, if we didn't need the output attenuators, it'd be much easier!

The reason I was asking about the trimmer is that I have been working on a triple VCO 28hp panel (see below). There's plenty of space in the front but that's going to be one hell of a PCB sandwich and if I needed to dig through all that to adjust the trimmer all the time, I'd just as well put it on the front. How are those trimmers mounted to the panel? Is it possible to power three VCOs from two power PCBs? Am I crazy?


This isn't final, just a sketch to see if I could fit everything I wanted to fit into 28hp.
diophantine
Isaiah wrote:
Diophantine seems to be the Synthasystem Master around here, I'm sure he'll chime in if you're looking for opinions on certain modules.

oops I wish I could lay claim to this title! 8_)

But yeah, I'm more than happy to help out with any module thoughts or whatnot! Should have the Sequencer done this weekend, leaving me only waiting for my next paycheck to pick up panels for my voltage processor, input amp, and tuner/monitor modules. Otherwise I have at least one of every module done. (Not sure if i will build any VCO-Bs.)

Just to lay it out there, probably the Triple EG and Frequency Divider would be the most unique and/or interesting in a non-Synthasystem modular. Of course, the VCF is great too and if you don't have a phaser, that is nice too. While i love having the VCA/Mixer combo, with a mixed system you may not find it optimal without an attenuator on the VC input. The +12/-10V offset range on the Selective Inverter, etc. is a bit extreme and again, in a non-Synthasystem setting, you may want to mod with a couple of voltage dividers.

Apologies for the slowness in updating the blog lately... jury duty + work + nearly dead laptop = ugh!
diophantine
Oh, and yeah, the V/Oct trimmer on the VCO is probably a tad overkill, if you are doing your own panels and are using the THAT ic with tempco, etc. Should be fine to just have it on the board. I got mine tracking nicely over 5 octaves - only reason I may have to readjust is if I get a frequency counter or a proper tuner.... my oscillscope has better resolution than my ears. hihi

Bleeps: best to ask David, but you might be able to get away with using a single power PCB for three VCOs. Or, at least, you could try it with just one! smile

If this triple VCO is going to be used in a non-Synthasystem mosular you might consider cutting down the size of the coarse knob and adding an attenuator for the PWM input. Perhaps even add the VC2 input with a regular attenuator.
bleeps
diophantine wrote:
you might consider cutting down the size of the coarse knob

sad banana

Quote:
and adding an attenuator for the PWM input. Perhaps even add the VC2 input with a regular attenuator.
Good call on the attenuator for the PWM. I can add that easily. Thanks for the input on the trimmer too!
diophantine
Of course, you can keep the big knobs! smile Just meant that you might have to if adding other attenuators or inputs.
bleeps
Here's what David said about a triple VCO/multiple VCOs from one PSU PCB in case anyone else is thinking about this:
Quote:
A triple VCO module would be excellent, and I can understand why you would like to have only one Power PCB for the trio.

It would probably be fine, but I would caution you VCOs can start to lock to each other depending on how the power supply cables are connected. Take Jurgen Haible’s Livign VCO trio. He put a separate power supply path and connector for each VCO on the PCB so each VCO was isolated from the other. One question people were asking about Jurgen Haible’s Living VCO was could you daisy chain these power supply connectors or do you have to run three separate cables to the main power supply? Turns out, this isn’t a problem on this trio, but I can’t guarantee you won’t see it on these VCOs if you tie all three to one PowerPCB, especially if the power cables are relatively short.

On another note, the Power PCB has three general functions. First, it lets the user build it to run off of basically any power supply that is commonly in use and thereby end up with +12 and -10 volts. While I think (and have heard) these modules should run form +/- 12 volts, for the VCO at least, in the pulse wave shaping circuit, and in the sine shaping circuit, there are some transistors which are connected to the -10 or “-V” signals and so have biasing set for -10 volts, not -12 . The bottom line is those circuits may have problems on -12, so I always recommend converting any minus supply to -10 volts.

Second, the Power PCB adds some general decoupling and filtering. Not a huge deal I think with how clean modern supplies are.

Third, on some modules, Nyle had additional filter/decoupling on the power supply lines. I’ve never really gone into the reasons why, I just made sure I included the option to have the extra filtering on the Power PCB. The VCO uses both the straight +12 and -10 from the main supply (regulated and conditioned on the Power PCB) as well as separate signal paths for the additional filtered +12 and -10 which are labeled V+ and V- on the schematics.

Bottom line is I think using one Power PCB for the trio would probably be fine electrically so long as you are sure to connect the straight +12 and -10 and the extra filtered V+ and V-. Beware you might end up with parasitic locking.

One other “form factor” hiccup for a shallow euro system is the HF Compensation mini PCB. Although when Nyle tuned my VCOs he disconnected the HF Compensation PCB, I think these days, most people don’t want all the “character” of the old VCO designs. You will need to figure out how to best mount these little guys if you want to use them.


I did forget about the HF comp boards. That will definitely add to the complexity of the build. Not sure what can be done to avoid the locking short of using all three PSU boards. I did a quick search here and at e-m and I couldn't find anything relevant.
diophantine
bleeps wrote:
I did forget about the HF comp boards.

Me too! I don't know how you intend to use these VCOs, but if you aren't too concerned with tracking (i.e. you aren't playing from a keyboard, or sending offset voltages to change notes & octaves, etc.) you may be able to live without them. With the HF boards I got mine tracking over 5 octaves, from 100 Hz to 3.2 kHz - but even without the HF board it was pretty close. (I didn't try anything beyond those tests, at least not yet.)
diophantine
Sneak peek for the wigglers:



w00t

Only "problem" was that I put a switch in upside-down. Fixed that in 30 seconds and otherwise it seems to work great!
Rod Serling Fan Club
dio - That sequencer looks great! With banana jacks and LEDs its like a rainbow in the dark.



I finally trimmed up my oscillator (sounds great!) and messed around with the linear FM mod some more. I no longer think that it is inverted but, I think it could use an amp at the input. It's a bit quirky but a fun timberal option as is. The exponential FM is great. Loving this oscillator, I need to build a second.
Isaiah
Diophantine
Your Sequencer looks great!
The combination of S-Trig outputs and banana jacks should prove very flexible!
I ordered a Sequencer PCB set from David last week.



Finally finished my first Synthasystem module (Noise Generator) today.
Getting some nice timbres by using the output to modulate the VCF Frequency on my SEM,
while varying the Level and sweeping between White and Pink noise.
The noise, at either extreme or any mix of White and Pink, sound quite pleasant and 'musical'.



Hope to have my Phaser, VCF, VCA and Triple EG completed in time for the Coventry Modular Meet this Saturday.
Everything is finished except the wiring and calibration (not looking forward to wiring the Triple EG! eek! ).
Rod Serling Fan Club
I think I've settled on the synthasystem I am going to build. I've already got 1VCO, both VCFs, VCA and EG built. I picked up a 6ux84 case and I think thats enough for a nice, compact system. I just ordered the rest of the PCBs. Here is what I'm looking at:
VCO A x2
VCA/Mix
VCF
Noise
Balanced Modulator
phase shifter
3xEG
Trigger generator
Sample & Hold
Voltage Follower
& CGS synthacon VCF
diophantine
Thanks RSFC & Isaiah!

(Sorry, didn't see your comments 'til now.)

The full pics are up in my blog. I need to get busy with the Synthasystem again... have been beyond distracted with jury duty (lasting from Jan 27 to May 16th!), plus waiting on stupid things like rack screws.

Rod Serling Fan Club wrote:
With banana jacks and LEDs its like a rainbow in the dark.

SlayerBadger!
diophantine
Isaiah wrote:
Hope to have my Phaser, VCF, VCA and Triple EG completed in time for the Coventry Modular Meet this Saturday.
Everything is finished except the wiring and calibration (not looking forward to wiring the Triple EG! eek! ).

Hope that all got done fine! The wiring on the Triple EG is definitely a bit of a pain; I'm planning to make 2 more, and will probably do them at the same time so that I only have to go through all the pain once more, haha.
Rod Serling Fan Club
I got my panels today! PCBs have been populated for some time. Now for some wiring & any troubleshooting then SlayerBadger!

diophantine
screaming goo yo SlayerBadger! !!!
MechaSeb
Hello guys !

Been a while since my first posts on this topic.

Actually i finished 4 of the planned modules : Phase Shifter, 2x Volt Proc/Mixer & Dual Volt Follower.

All of the others PCB are almost finished to be populated and i'm waiting for some components regarding the build of 2xVCO, 2xVCF, 2xVCA & EG. Can't wait to starting up building the earth of the system.

A picture of my first attempt in building a cabinet:



And another one of the built modules :
Picture file
MechaSeb
And an another one : Input Amplifier. Had a bit of trouble with one of the SPDT switches but now, it works !! applause
Rod Serling Fan Club
looks nice mech
synthcube
Just as soon as all my panels arrive from epinasty (custom copper! smile ) I'll have a lot to post-- all the modules, etc. Wat a great system. Thanks Nyle and David!
MechaSeb
Just finished my 13rd module yesterday. applause

Next coming : 4x VCO, Sequencer & Env then 2x Trig Gen, another VCA/Mixer.

I'm working on the second cabinet right now.
Isaiah
I've decided to build all my unfinished and future Synthasystem modules with banana jacks.
The panels are natural aluminium with black knobs.
I plan to use red banana sockets for Gate inputs/outputs,
but can't decide on black or grey for audio & CV inputs/outputs.
Black might feel a little overwhelming along with the black knobs.
What do you think?
MechaSeb
i personally really dig the old banana schema color from the Synton 3000 modular. But with natural aluminium i'd probably go the same as Serge.
Isaiah
The Synton 3000 is black inputs and blue outputs, right?
Looks cool!


I'd like to keep red for gates (a la Serge).

The Serge standard is black for bipolar and blue for unipolar voltages.
I believe that the blue and black sockets are of much greater importance in Serge systems because some circuits only produce, or respond to, positive audio and CV signals.
Other than the Triple EG outputs (and gate signals), all the Synthasystem modules (if I remember correctly) are capable of producing and handling bipolar signals.
So, it seems to make sense, in the context of the Synthasystem, to only differentiate between audio/CV and gate signals in terms of colour.

So, black or grey?

I should add that it was by looking at Diophantine's system and then thinking for some time that I came to this conclusion. So, many thanks to him!



I had thought about different colours for CV/Audio and Gate inputs/outputs.
But, that would mean 4 different colours and a new standard to "learn" (not that it would bother me, just makes it easier for friends and bandmates. All the inputs/outputs on the Synthasystem are labelled as such, too).
synthcube
epinasty is working on this full set-- not everyone's cup of tea, but it will be a work of art when completed

negativspace
MY ASS IS BLEEDING
MechaSeb
Quote:
epinasty is working on this full set-- not everyone's cup of tea, but it will be a work of art when completed


Niiice ! thumbs up Looking forward to seeing more.

Mine is not yet finish but i'm already in love.
Need 3U more for the second Sequencer & the Microcon and i'll be done.

Isaiah
Fantastic!

Curious to hear how you plan to arrange the modules (individual "voices" or, say, all VCOs together).
MechaSeb
I'll probably go for two "independent" 9U systems. Each one would get at least a sequencer, one triple enveloppe, two vcos, one vca, one volt/proc mix and all of the other modules scattered between the two systems.

What about yours Isaiah ? thumbs up
Isaiah
That makes sense. It allows you to use each 9U independently (each contains a sequencer and enough modules for a "voice").

It looks like one of your VCO Bbs has an LED where the Fine control normally is.
Is that to monitor the Sine output?
I had been thinking about doing the very same thing on my VCO Bb (it will be used as an LFO, too) and maybe both of my VCO As.



The plan for my system is a 10U case (9U of modules and a 1U utility strip).
By the way, all of my modules will have bananas, not 3.5mm.

SYNTHASYSTEM
Input Amplifier
Peak Selector
Voltage Follower
Tuner / Monitor
Sequencer

VCO A
VCO A
VCO B
Noise Generator
Phaser

VCF
VCF
VCA
VCA
Triple EG

UTILITY STRIP
Format Jumbler (Banana - 3.5mm & 6.3mm)
Maybe some Fonik Attenuvertors and a CGS DC Mixer
PSU connection and On/Off switch

SUBSTITUTE MODULES
Voltage Processor
ARP 4035 VCF (14HP Transistor-Ladder)


My thoughts/goals in designing this system are:
*A modest, but solid foundation of East-Coast synthesis that I can use as the centre hub of my setup (I always think of that photo of Chris Carter in his studio with his Roland 100M and other Roland stuff. I have a Boss Dr-55, too!).
*Multiple voices. For example, one sequenced and one played with a keyboard.
*A monosynth voice that is quite different from my SEM (3 VCOs, 2 VCFs + Phaser, Noise etc).
*A portable, playable system that I can gig with.
*Live processing of non-electronic instruments in a band (drummer driving the Sequencer with the Peak Selector).
*A system that will be easily expanded and integrated with my planned 4U Serge-like DIY.


It does, however, mean I miss out on some of the more esoteric Steiner Modules (VC Trigger Generator, Selective Inverter).
I do plan to build a Steiner Duophonic Keyboard, so I'm tempted to pull one of the VCO As to make a simple Steiner keyboard monosynth.
That would afford me the space for some of the more unusual modules, but I'm really not sure yet. I may just have a 3U rack of supporting modules (including the substitutes) that stay at home and don't go to gigs.
Hmmm...

What do you think?


I'd really love to hear any recordings you've made with your system!
Also, you have a Serge modular, right? Ignoring the format jumbling, how do you find the two systems complement each other?
MechaSeb
Isaiah wrote:
What do you think?


Sounds good to me. Haven't yet finish/try both the VC Trig Generator and Selective Inverter so i can't reply significantly but they seems to be pretty "simple but enough esoteric" modules, yes. Back to your module list, i would personally add at least one Voltage Processor/Mixer. It's a really nice and versatile module and highly useful in doing CV processing !

Quote:
I'd really love to hear any recordings you've made with your system!


Check this link : https://soundcloud.com/mechaseb/sets/synthasystem-synthesizer-demos
I'm going to add more demos soon (VCO etc.).

Quote:
Also, you have a Serge modular, right? Ignoring the format jumbling, how do you find the two systems complement each other?


Yes, i'm a lucky enough to have got some Serge. They're really different beast so naturally, they complement each other really well.
Like you, i basically was looking to build an East-Coast system which still have nice features and "not seen anywhere" modules. I found the Synthasystem answering pretty well my select criterion. Also i wanted something which sound fat and "vintage" and here again, the Syntha was the perfect gear for this.

Edit: The LED on the VCO Bb is not yet wired and was placed here just to check if it would fit well or not. I'm not sure how to implement the Led though but i still think to do it in the future.
Isaiah
Sorry, I missed your reply before.

Thanks for the Soundcloud link.
I don't need to tell you how great it sounds! hihi

Can't wait to have two Steiner VCFs functioning together.
Sounds so fantastic when overdriven, that it's easy to overlook the more mellow tones it can create.
Try patching a VCF output into all three inputs on a VCA/Mixer - It's possible to overdrive the VCA.



I've decided to drop two 7HP modules so I can include a Voltage Processor/Mixer (thought about it some more - thanks for the tip!).

Tuner/Monitor will be built into the utility strip instead of a module. I do consider it a utility and not really a synthesis element.

I can't decide whether to keep the Peak Selector or Voltage Follower.
The former would probably only be used occasionally.



I believe the LED on the VCO could be realised with Ken Stone's LED Driver PCB.
However, it would only track the positive half of the waveform. Hmmm...
magman
It's time I got my Synthasystem PCB's out of my backlog and get them working.

I've decided to build the modules I've got as a companion panel to the Best of CGS panels I've already built, so that means a 4U panel and banana sockets. I have the following modules in my stack:
    VCO
    VCO Ba
    VCO BBQ
    VCF
    Mixer
    Frequency Divider
    Triple Envelope Generator
And here's my first pass at a panel:

https://www.dropbox.com/s/1dzes09by7ws3bw/Best%20of%20Panel%2021JAN201 3.pdf

I'd appreciate any comments or criticisms on this design as it stands, before I commit to making it. For example, I'm tempted to break the grid for the switches on the Frequency Divider, to give me more space behind the panel for the rotary switches.

Time to get on with building some PCB's.

Regards

Magman
negativspace
@Isaiah If you're not opposed to doing a little LED driver on perf, try the opamp-based circuit from the CVP. (Schems in the thread.)

@magman I love the panel! If you need some small, super high-quality rotary switches, check out these Grayhills. They're smaller than 16mm pots so you won't need to alter the grid.
magman
Thanks negativespace. I have seen these switches before, but Goldmine don't deliver to the UK. New versions of these switches are available from some of my local suppliers, but they are £12-15 each, so I will use them only if I have to.

A couple of people have expressed an interest in the Inkskape version of this panel as well, so I have attached it here for people to pick up as needed.

https://www.dropbox.com/s/70p33193hy7hhqv/Best%20of%20Panel%2021JAN201 3.svg

Although some of the horizontal divider lines are positioned mathematically correctly, I suspect I may end up moving them a mm or two for a better look as well.

I've started populating the PCB's now, almost time to start making a prototype panel.

Regards

Magman
negativspace
Let me know if you want some of those switches, then... I do ship to the UK and would gladly pass some along.
dingebre
Hi everyone! I just found this thread (thanks Mike) and I can't tell you all how happy this makes me. I am really impressed with what has been done.

I can also tell you Nyle is really flattered by the attention to his designs. He was just happy I was putting his hand drawn stuff into a more permanent and organized form. When I asked if I could share the electronic versions, he was all for it and is very interested in how it has been received.

Thanks for helping to keep this stuff alive and for making music with it. This is the best payback I'm getting out of the project. Which is a good thing since I'm very, very far away from recouping just the out of pocket expenses, much less the 100s of hours staring at Eagle smile

Please remember to contact me with any questions or suggestions. I'll do my best to help.

David
synthcube
not everyone's cup of tea, but here are some more of the synthasystem panels that epinasty is running for us... the full system built on David's awesome PCBS will include the following modules:

Quadulator 1&2
Sinulator
Sawcillator
Thrumulator 1&2
Tricuspidic Mandiblator
Amplitoder
Disretarder
Superflueventer
Simplificator
Slewminator
Wahptor
Improbulator
Enhancomancer
Plasticator
Reundivisor
Thrumper
Clipfester
Eloquantizer
Unrestrainolator
Digivoltimizer

synthcube
here's the first assembled unit

we are really proud of the work, and grateful to nyle, david, and luigi for making it happen

Rod Serling Fan Club
Great panels! The full system should look really wild. What kind of case do you plan to put them in?
Jarno
I think those a great knobs, I have them on one of my basses as well, but not sure if these are the best for these panels.
Maybe Epinasty needs to start making knobs as well?
Something like chickenheads in beige or brown, maybe aged and somehow with a "craquele" finish?

Still looks great though, like the steampunk stylee.
thumbs up
Rod Serling Fan Club
I've seen brass knobs that look similar to those. One can remove varnish from brass and use salt water or vinegar to age/patina brass.
Jarno
That would match the look of the panels very well, I guess!
synthcube
you guys are right on.... i need to find a different option for the knobs... will keep at it

have not sorted out a case yet... has to be the right look and feel
Jarno
Cobwebs, steam exhausts Mr. Green
Rod Serling Fan Club
Here's one of the first patches I put together after putting all the modules in the case. It's just a bunch of crazy FM noise stuff, nothing too special. If you want me to show something in particular, let me know. Unfortunately I don't have a sound card at the moment so will just be posting lo-fi videos.
Isaiah
Rod Serling Fan Club
Fantastic!
I love the Synthasystem Phaser just as much as the VCF.

I'm interested in hearing some examples of tonal (melodic) FM, please!
From Mellow to Unpleasant thumbs up
Also, VCO Sync sounds, please.
Rod Serling Fan Club
OK, here is some quick sync action. I wish the audio was better. The camera muddies the sound and cuts some of the lows and highs but it'll have to do. The extra noisiness was from having both oscillators on the output. Sounded neater/meatier in person but the video recorder kinda made it sound more noisey and cut out some of the low end. anyway...

It was sequenced by a minibrute. The synthasystem sequencer was clocked by the minibrute gate and used through a slew as a long envelope to sweep the frequency of the synched oscillator. Just the two oscillators straight to the mixer and out.



MechaSeb
Wow RSFC your system looks really great.
May I ask what is your case ?

And I agree with you guys, the phaser as far as subtle it is, is awesome in every patch. The VCO synch also have to be noted. A bit à la SEM razz

(Need to debug my Sequencer and finish my EG)
joshuagoran
I'm late to the party but this is a great thread! I really dig the different directions some of the systems here took...RSFC compared to Epinasty/Synthcube, nice contrast! How did y'all do the copper panels? I have a couple projects that I've wanted to do a more subtle something like that with

Now that folks have played with these more perhaps, are there certain modules that fit in with an existing Euro system better than others? Seems like folks particularly like that phaser, VCOs, and the VCF?
synthcube
The brass or copper antiqued panels for our synthasystem are the artistic genius from epinasty.. We provided the steampunk naming conventions and some design inspiration to create the full line of panels... And coming soon is the Thrombulator, (steampunk version of the Steiner Microcon) in antiqued copper to match. smile
The line was motivated by a frac size e350 one off that epinasty did a few years back.
At a minimum, the quad VCO, VCf, phaser, slew limiter and frequency divider might be good adds to a system...
Part of what makes the synthasystem line interesting is you have the option of using David's traditional FPE files , the forthcoming clarke68 panels , the epinasty copper or brass versions, or pure DIY. We hope to do frac and MOTM panel versions too.
elmegil
Oooh dare I hope MOTM brass? :-D
synthcube
The MOTM purists would have us tarred and feathered smile
negativspace
Reason enough, IMO. hihi
Isaiah
I think I've finally decided (for real this time!) what my system will include.

9U 98HP case

Sequencer (56HP)
Voltage Follower (7HP)
Peak Selector (7HP)
Triple EG (28HP)

Input Amplifier (7HP)
Processor / Mixer (14HP)
Noise Generator (7HP)
VCO A (28HP)
VCO A (28HP)
VCO Ba (14HP)

Ring Modulator (7HP)
Phaser (7HP)
VCF (14HP)
VCF (14HP)
VCA (14HP)
VCA (14HP)
Spring Reverb (7HP) (from MusicThing)
Stereo Monitor (7HP)
PSU (14HP)

Rockin' Banana!
Rod Serling Fan Club
Nice selection. I think a spring reverb is a great addition to the synthasystem. It fits the vibe so to speak.
Isaiah
Rod Serling Fan Club
Thanks, I think so too hihi

I don't think I ever responded to the second Synthasystem video you posted, sorry.
Thanks for sharing them! The VCO Sync sounds great.
I've been listening to those two videos and (in my head) the Rocky soundtracks (I-VI) for motivation!
Can't wait to finally get the panels!

Is your case 90HP with sliding nuts to squeeze the extra 1HP in?
negativspace
Agreed on the spring reverb... and I don't even like spring reverb. But it sure fits the vibe of these modules. I'm really looking forward to having a case dedicated to the Synthasystem and expanding my (wee) system. That might be something to consider.
Rod Serling Fan Club
I hate those videos to be honest. The microphone on my video camera ruins the sound. Eventually I'll get around to better audio recordings.
Rod Serling Fan Club
That is to say, your system will sound better than those videos :)
Isaiah
My panels have arrived so my system is set in stone (woah) which is good because I kept changing my mind all the time.


10U 84HP case.

TOP ROW
Sequencer (56HP)
Voltage Follower (7HP)
Peak Selector (7HP)
Processor / Mixer (14HP)

MIDDLE ROW
VCO A (28HP)
VCO A (28HP)
VCO Ba (14HP)
Noise Generator (7HP)
Phaser (7HP)

BOTTOM ROW
VCF (14HP)
VCF (14HP)
VCA (14HP)
VCA (14HP)
Triple EG (28HP)

1U UTILITY STRIP
Input Amplifier
Stereo Monitor (functions as headphone amp, or audio output)
Banana-1/4" adaptors
Mains input and power switch

ADDITIONAL MODULES
Ring Mod (7HP)
This will be swapped in and out as needed.
It wasn't quite essential for me like the other modules, but I didn't want to miss out completely.

E-MU SSM LPF (14HP)
This uses an AMSynths AM8040 PCB and is just a standard 4-pole SSM2040 (HM2040) VCLPF.
Haven't designed a panel yet so I'm not sure whether to make it fit the aesthetic of the Synthasystem as a substitute module, or keep it in its own rack.



I must say, seeing my Doepfer LC6 full of just the panels (bananas and panel hardware in place) for the middle and bottom rows is very satisfying.
It has killed most of my daydreams of building various things.
Of course, it doesn't produce any sound yet, so that might change, but I hope not hihi

Got to make a format jumbler for testing, then I'll wire up the populated VCO B, VCF, VCA, Noise, Phaser and Sequencer PCBs.
Then I'll order the case from Ross Lamond and the 1U utility strip while I start the remaining modules.
Phew...

I'll post photographs as I progress thumbs up
synthcube
that's a fantastic system and set of modules! Cant wait to see the pictures.
minime123
love the synthasystem!
mini
Isaiah
Thinking about adding a mod to my Triple EG and just wanted some thoughts.

I'm using bananas so I lose the convenience of switched jack connections (EG inputs chained 1>2>3).
If I want to trigger all the EGs at once, I have to use two cables.

I'm also using V-Trigs, but the S-Trigs are available on the PCB.
By using switches to short between the EG's S-Trig inputs, you can replicate the OR gate functionality of the original Synthasystem, but with V-Trig inputs.

Taking that a step further: connecting EG1's S-Trig in via a switch to the anode of a diode, and the cathode to EG2's S-Trig in.
With the switch open, the two EGs function independently.
With the switch closed, a gate applied to Trig 1 in triggers only EG1, but a gate applied to Trig 2 in triggers EG1 and EG2.
Pretty cool!



So, wigglers, the question now is which arrangement of EG cascading will be most meaningful?
Perhaps this:
EG 3>2>1
EG2 can be triggered by EG3's input,
EG1 can be triggered by EG2's input.
With both switches on, a gate applied to EG3's input would trigger all EGs.
I think this makes the most sense as EG3's output can be combined with the outputs of EG1 and EG2, this almost allows for a kind of crude ADSR (EG1/2=AD, EG3=ASR) with retriggerable AD cycles.

What do you think?



NOTE:
Yes, I could account for all cascading arrangements using three On-Off-On switches, but it's a pretty cramped panel and I don't really want to add three switches, especially ones that can be easily knocked into a different setting.
dingebre
Thought I'd post here, too. New website is open:

www.analoguerealities.com

All the Synthasystem PCBs are in stock. I'm also getting everything ready to re-stock a good number of all the PCBs.

Here is a photo of my current setup. Mostly Steiner with a smattering of MOS LAB, COTK, Synthesizers.com, and my own Moog clones. A bigger size is on the website that you can zoom in on.
dingebre
Isaiah wrote:
Thinking about adding a mod to my Triple EG and just wanted some thoughts.

I'm using bananas so I lose the convenience of switched jack connections (EG inputs chained 1>2>3).
If I want to trigger all the EGs at once, I have to use two cables.

I'm also using V-Trigs, but the S-Trigs are available on the PCB.
By using switches to short between the EG's S-Trig inputs, you can replicate the OR gate functionality of the original Synthasystem, but with V-Trig inputs.

Taking that a step further: connecting EG1's S-Trig in via a switch to the anode of a diode, and the cathode to EG2's S-Trig in.
With the switch open, the two EGs function independently.
With the switch closed, a gate applied to Trig 1 in triggers only EG1, but a gate applied to Trig 2 in triggers EG1 and EG2.
Pretty cool!



So, wigglers, the question now is which arrangement of EG cascading will be most meaningful?
Perhaps this:
EG 3>2>1
EG2 can be triggered by EG3's input,
EG1 can be triggered by EG2's input.
With both switches on, a gate applied to EG3's input would trigger all EGs.
I think this makes the most sense as EG3's output can be combined with the outputs of EG1 and EG2, this almost allows for a kind of crude ADSR (EG1/2=AD, EG3=ASR) with retriggerable AD cycles.

What do you think?



NOTE:
Yes, I could account for all cascading arrangements using three On-Off-On switches, but it's a pretty cramped panel and I don't really want to add three switches, especially ones that can be easily knocked into a different setting.


Sounds workable. The beauty of SDIY is not only can you pick and choose the modules you build, but you can customize them to meet your needs and style. What you propose can no doubt be altered later if it needs to be.

David
negativspace
Beautiful system you have there, David! It's motherfucking bacon yo
Isaiah
I completely forgot to mention that David was kind enough to test functionality of the above mod in his system.
Thanks again!

If I label the switches TRIG LINK, it's vague enough that I can change the arrangement by swapping the headers on the EG's S-Trig inputs.
I guess that's decided then!

Yes, what a cohesive, inspiring system.
Give us some audio, David! Rockin' Banana!
diophantine
Isaiah thankfully reminded me of this thread!

Here is my completed system:


I finished it about a year ago, and have given it quite a bit of use then then. One of my initial goals in building the system was to have a very direct system where I didn't have to choose between VCOs, VCFs, etc. I'm happy to say it fills that role perfectly, and it sounds great! Quite often it'll be the first synth I patch up when I go into the studio (for those reasons mentioned) and it nearly always ends up in a recording.

The only mods I ended up doing were due to the use of banana jacks: internal/external switched on the S&H, pull-down resistors on the VCAs (probably not necessary), and no normalizing on the Triple EG (not really a mod, just an omission).

I went with S-Triggers, which I knew was a risk, but I have no regrets. The only "gotcha" is the trigger I/O jacks on the sequencer - try and OR something off of that and you end up triggering the sequencer. This is obvious, but sometimes in the heat of patching you don't think of it... Otherwise, being able to OR these signals - particularly the stage outputs of the sequencer - is great.

I'm also still happy I went with banana jacks. They help with the S-Triggers, and I have had no issues. I since have built a TTSH and Frac system with minijacks, and still have no regrets on using bananas with the Synthasystem. It feels solid, and loses no meaningful functionality.

There's still some modules that I haven't had time to play with enough, a few modules that don't get much use that I may end up replacing, etc. I will document that later. I'm actually hoping to make some videos about these modules; we'll see if that happens.

I plan to built a utility panel in the bottom U, with S-Trig/V-Trig converters, TS/Banana converters, and probably a PAiA Hot Springs reverb (or two?). I have 3 VCA/Mixers, and was planning to use the 3rd mostly to mix modular signals with reverb, since the Hot Springs doesn't include a wet/dry mix (unless my memory is mistaken).

Long story short, this is an excellent project! Everything sounds great and works well together. I couldn't be happier having done this as my first fully DIY modular project. It is getting a ton of use. And it is an extra plus when friends come over and have fun using it, especially folks like Steve Roach who got to use the originals back in the 70s!
dingebre
This is brilliant! Thank you for the photo and description.

David

diophantine wrote:
Isaiah thankfully reminded me of this thread!

Here is my completed system:


I finished it about a year ago, and have given it quite a bit of use then then. One of my initial goals in building the system was to have a very direct system where I didn't have to choose between VCOs, VCFs, etc. I'm happy to say it fills that role perfectly, and it sounds great! Quite often it'll be the first synth I patch up when I go into the studio (for those reasons mentioned) and it nearly always ends up in a recording.

The only mods I ended up doing were due to the use of banana jacks: internal/external switched on the S&H, pull-down resistors on the VCAs (probably not necessary), and no normalizing on the Triple EG (not really a mod, just an omission).

I went with S-Triggers, which I knew was a risk, but I have no regrets. The only "gotcha" is the trigger I/O jacks on the sequencer - try and OR something off of that and you end up triggering the sequencer. This is obvious, but sometimes in the heat of patching you don't think of it... Otherwise, being able to OR these signals - particularly the stage outputs of the sequencer - is great.

I'm also still happy I went with banana jacks. They help with the S-Triggers, and I have had no issues. I since have built a TTSH and Frac system with minijacks, and still have no regrets on using bananas with the Synthasystem. It feels solid, and loses no meaningful functionality.

There's still some modules that I haven't had time to play with enough, a few modules that don't get much use that I may end up replacing, etc. I will document that later. I'm actually hoping to make some videos about these modules; we'll see if that happens.

I plan to built a utility panel in the bottom U, with S-Trig/V-Trig converters, TS/Banana converters, and probably a PAiA Hot Springs reverb (or two?). I have 3 VCA/Mixers, and was planning to use the 3rd mostly to mix modular signals with reverb, since the Hot Springs doesn't include a wet/dry mix (unless my memory is mistaken).

Long story short, this is an excellent project! Everything sounds great and works well together. I couldn't be happier having done this as my first fully DIY modular project. It is getting a ton of use. And it is an extra plus when friends come over and have fun using it, especially folks like Steve Roach who got to use the originals back in the 70s!
MechaSeb
So beautiful diophantine love love
Funny enough i've started again this project.

Just fisnihed the Frequency Divider (such a simple but eleant & fun module by the wway !) and have a question about it's functionnality. Everything seems working except when i input a square wave, the bottom row Octave Select doesn't give me 5,9 neither 15 division. I have only a division of 3, 7 & 11. Meanwhile it looks like it's working as it shloud with a trig input signal. Is that the normal behaviour ?
dingebre
MechaSeb wrote:
So beautiful diophantine love love
Funny enough i've started again this project.

Just fisnihed the Frequency Divider (such a simple but eleant & fun module by the wway !) and have a question about it's functionnality. Everything seems working except when i input a square wave, the bottom row Octave Select doesn't give me 5,9 neither 15 division. I have only a division of 3, 7 & 11. Meanwhile it looks like it's working as it shloud with a trig input signal. Is that the normal behaviour ?


I'm sending an email. This is not normal behavior. The input is vest when there is a sharp edge on the signal, square wave or sawtooth.

David
dingebre
Just a ping to the thread.

David
Isaiah
Some wonderful Synthasystem Sketches by the great Todd Barton:
http://youtu.be/gquxjZe_O-s
dingebre
These are great videos. I grabbed a bunch of still frames so I could try to duplicate his patches. I also loved the Microcon and Synthacon videos he has also published.

Thanks for posting the link.

David
MUFF WIGGLER Forum Index -> Music Tech DIY  
Page 1 of 6
Powered by phpBB © phpBB Group