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The Synthasystem Discussion and Appreciation Thread
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3, 4, 5, 6  Next [all]
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
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