Surplus Synthesizer PCBs on offer


I’m ready to get my synth PCBs manufactured, and I will have a surplus as minimum order quantity is 5 and I only need one set (maybe two in case I screw up the assembly :wink: ).

Is anyone here interested in a set of PCBs of the following circuits:

  • 2x Yusynth VCO
  • 2x Yusynth “Minimoog” VCF
  • 2x Yusynth VC LFO #2
  • 2x Yusynth ADSR
  • 4x Yusynth VCA, DC version

These come on 2 boards measuring 200mm x 150mm each.

If you’d like a set you please let me know, and I’ll also privately provide the BOM and some other design details. Unfortunately I cannot publish the complete designs of the synth (especially the EDA files) since they are based on Yves’ (Yusynth) design and there is not a clear license for doing so other than “non commercial use only”.

The price of a set would be “buy me a beer sometime” :slight_smile:

I also have some (actually, about 20) compatible PSUs available for these; they are switch mode +12/-12/+5. I’ll update here later with exact make/model.

I’ll be ordering these probably some time in the coming week or two.


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Hi Doug,
If be interested if they’re eurorack compatible. Happy to chip in towards your costs.
I’ll be doing an order of some module boards in future so I will probably make the extras available with those too.

Hi @mikekelly - the boards are eurorack voltage compatible (+/- 12V) but not in size/form. Reason being that my synth build project is not truly modular (the modules will not be removable/replaceable).

Also in line with the circuit designer’s wishes, I have to make this a non-commercial exchange, so perhaps a board swap in future would be the way to do it? :slight_smile:


OK, got you. I’m up for board swaps but as these are too big for Eurorack I should let someone else jump in and get your spares this time.
It’d be good to see how your system turns out, give me a shout if you need any help with the build.

Hi @doug!

This is something I would be interested in! I don’t really know what I’m doing with hardware synths, but I’ve programmed a few in software before, and have messed around with electronics a bit - analog synths is something I’ve been looking to get into for a while now :slight_smile:

I’d be interested in one of those psus as well. Happy to reimburse for those.



That’s cool. This project of mine started some years ago for the same reason… looking at pictures of cool looking old fashioned synths and thinking that I would like to have one :slight_smile:

The PSUs are “Advanced Power NA055P300”; 55W; +5V @ 3.5A, +12V @ 3A, -12V @ 1A. I can’t find anything about them on the internet, seems like a small time UK company made these some time ago and there’s little trace left of them.

I suggest you first read here: as he does have some basic explanations of each circuit.

I’ll post back here when I’ve got the PCB order in. I have a few small tweaks still to make to the design though to ensure it all matches up with the required panel wiring.



The boards are ordered! :smile:

Once I have them I will bring the surplus and a couple of PSU to a Thursday evening at SLMS, I’ll let you all know when that will be.


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Look what arrived :grin:



I haven’t forgotten about this - I’ve just been busy assembling the thing! I will come by the space in the next few weeks and deliver on my promise of bringing stuff to share. I might also even have a working synth to show at that point :slight_smile:



I’ll be popping into the space this evening with PCBs and PSUs … finally :slight_smile:

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looks incredible!

It’s coming alive…

Working so far:

  • 2x VCO (except sinewave outputs, level is 1/10th of expected)
  • 2x LFO
  • 2x ADSR

Wired up but not working correctly:

  • 1x VCF (no output)
  • 1x VCA (output being held at constant +12V)

Still in development

  • Digital interface

If anyone wants to see, test, help etc I will come for electronics night this Thursday.


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I have fixed successfully fixed a couple of the issues on my own :slight_smile:

  • VCF had a transistor inserted back to front
  • VCA had an opamp with +/- inputs reversed

I’m waiting for some PCBs to arrive for the digital section, then I think I will bring it to the space to show off demonstrate what it can do :wink:

If anyone has any thoughts on these remaining points, I would be grateful:

  • How to secure the top panel in place
  • Suitable mains switch and wiring



hi doug nice work i woul d kike to see the ciecuits can u send a link oe some more info on the pcbs yes bill of materials i have octave a midi to cv unit now ineed a vco white pink so on been runins simulatio ever seen the transedent 2000 on te web an obsolete uk kit i have one n circuits in peotes isis circuits from some old books mark space and sawtooth

Hi Mark,
I took all the circuits for this project from - you will find there the schematics and BOM for many common modules.


yes thanks i looked at the link i have a midi to cv and adsr
now need a sound scourse
ssm chip is expensive

so any bords left ?

Hi Mark,
Yes I have 4 sets of boards left, but I currently put them into storage as I have now packed up the materials I used for this project so I can move on to the next.
Next time I’m at the storage I will fetch a set and deliver them to the space in due course - it might take a few weeks, but feel free to remind me if you don’t hear back.


Hi Doug, I’m getting started in modular, would I be able to nab a set of boards at some point? Your project looks great, have you made anything with it yet?

Hi Sia,

I’ve mostly only played with it interactively as a sort of noise machine; I still haven’t finished the digital interface to be able to play actual notes or melodies on it.

I will pick up a couple of sets of boards this weekend, I can subsequently drop them off at the space probably on the following electronics night (Thursday 30th).

There’s a couple of errors on the PCBs I need to document as well, they will require minor modification to work correctly - but this is easy enough to do and takes a few minutes.