Fixed-Architecture Mono Synth Builds

Forgive me if this is in the wrong place, or if this has already been covered. I have been trying to find more information on this subject, but alas have not been able to get my bearings.

Nyström Mono

I was inspired by Albert Nyström’s monosynth on youtube because of its simplicity and my confidence in assembling it. I’m coming at this from being able to make effects and various filter modules on stripboard. I’ve never built a synth but I follow stripboard diagrams well. I’ve done PCBs as well and I’m wondering if incorporating both in my build is a bad idea.

Should I approach designing my synth differently than one would a modular, aside from the obvious things like wiring/enclosure/panel?Is fixed-architecture overly ambitious? I’m doing it more for preference because I prefer simple synthesizer interfaces, like Albert’s mono. The Juno 60 was my first love.

Also, what are some less obvious considerations, e.g. voltage across different schematics I’m using, etc.? What are my limitations in this format aside from patching limitations? What are some resources I may have missed? Sorry if I sound obtuse. It just seems more complicated than building any kosmo modules i want and wiring them together in a “fixed architecture” format and putting them in an enclosure. I understand there’s a lot going on. I need a PSU (dual I assume), a signal flow of my design and choosing, portamento/glide, probably an arturia cv/gate keybed from Reverb, maybe a chorus/delay etc etc

Assuming I have all the time and patience in the world (not walking for another several months), forgetting I am an ignoramus, what is your advice for me in terms of designing this, assuming I want to build almost an identical synth to Albert’s, with minor changes to effects (analog), and I’d love a sequencer?

Thanks for reading, looking forward to any and all responses. A lot of you are big inspirations here.

Jesse / Warmwood

Take a look at some of the fixed-architecture designs that are out there already. For instance the Sound Lab Mini-Synth Mark II and the Sound Lab ULTIMATE from MFOS. There probably are others I’m not thinking of at the moment and maybe someone else will. Even if they’re not exactly what you want or close enough, studying their design may be helpful in figuring out what you want to do.

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I’ve spent hours over there. This has been very helpful, thank you.

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The building blocks are the same, your just removing the flexibility/complication of the modular. adapting euro/kosmo designs is fairly simple as you basically removing the unwanted jacks and features. so long as you stick with the same power and well trodden designs, it should be straight forward.

Plan out your signal path and the block design it from there., what you will probably find is you build a fixed format out of modules.


As you are avoiding a lot of the external interfacing that modulars provide, a fixed-architecture design should be simpler than an equivalent modular. Modules often need extra input/output buffers and protection to standardise voltage levels, etc., whereas signals wholly internal to a synth do not have the same constraints.

If you are daunted by the apparent complexity of a complete synth, build and test it section by section, perhaps starting with the VCO.

As for stripboard, or mixing stripboard with PCBs, there is nothing wrong with that. Making your own PCBs can be a time saver if you are making many copies of a circuit, I use stripboard a lot for it’s convenience and adaptability, especially in prototyping. And you say you have experence with stripboard, which helps. A stripboard can look good if you design tidily.

Good luck!

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This is an example of a fixed architecture design, I started with the DCO’s and MIDI interface to get a stable 2 voice oscillator. Then I moved onto the portamento circuit followed by LFO for modulation. I then added the envelope generators and finally the filter/VCA section. You can see from my photos how it started and grew.


I would say that besides the triple oscillators and sync, what makes that synth sound so good is the add on effects processor, I would like to incorporate one into one of my designs, but getting hold of that module for me is currently impossible as no one is shipping to the ukraine that stocks it.

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Thank you so much. Hearing from some my inspirations here, very cool. Craigyb - your work has been really intriguing to me. The Juno 60 is my fav synth of all time, so hearing your poly and seeing it made me really excited. That being said, I have about one week of experience in programming a robot in C++ about 25 years ago…I find all the Rasberry Pi and Teensy stuff very overwhelming, but I want to look into it more. Nystrom made a poly with a teensy for $120 and it sounds incredible. Yours is about ten levels up and I am no purist, just trying to stick with what I “know” for a mono synth. Will build a simple drum machine to learn more of the “programming” side before going into the poly world like you have done. Though that is ultimately the dream.

At this point, you all confirmed my suspicions about building modules and blocking em together. I guess all I’m left wondering is, going to what twinturbo said about power…do all my circuits need to be at the same power rating?

That leaves the question: how can I get something ready to go, dual power supply presumably switchable (but that is dependent on the previous question about them all needing to be the same voltage) without blowing myself up? I don’t think I can be convinced to build one after reading the MFOS disclaimers yesterday and other stories. I don’t often misread schematics but I have a family and I can’t walk, so I can’t afford the risk. And then, looking at MeanWells and other PSU solutions left me feeling more lost than ever about how to provide power to a relatively small amount of modules, without having to do any dangerous wiring. I’m not really down to put a noisy PC PSU in either.

Thanks again everyone!

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Craigyb - when you said “what makes that synth sound so good,” to which synth were you referring? Also curious which effects chip you’re talking about. What is the magic one you’re waiting for?

I’m referring to the nystrom non you posted originally, it has an off the shelf effects processor built in at the end that uses a PT 2399 chip. You can see the led display showing the current preset number. I think it has 99 preset effects.

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Ah gotcha. I was gonna put my own V3205/MN3007 delay/chorus unit in it.

Yeah it could easily be substituted for whatever you want. I guess it’s just on the end of the audio chain. I’ve built June-60 chorus units into mine as they are so cheap to buy and I can control them from the Teensy.


See some of the previous discussions, e.g.

I’d say there’s nothing particularly dangerous about building a wall wart supply. Main thing is to make sure the capacitors are not backwards! If you don’t build your other options are to go with something like Mean Wells — but that requires connecting wall voltage, which you definitely should not do if you are not knowledgeable and confident about working with that, or to buy an off the shelf Eurorack supply and use that somehow.

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Thank you! I have spent so much time pouring over Ray Wilson’s Wall Wart supply and it looks incredibly easy and all I could see that could go wrong is capacitor placement…but I’ve seen so many people warning about it w/o explaining themselves. I definitely do not want to do any mains wiring. I get it in principle, but having no experience cancels that option out.

I’m gonna do Ray Wilson’s PSU, if anything in his honor, and because I have his book I can follow from. I need something to test the modules too.

Okay, one more question: removing the eurorack patch jacks from wiring diagrams…looking at different VCO stripboard diagrams, they all seem to have them. At least the 3340s I’m looking at. If I want to remove them, do I replace them with switches? Or just remove them altogether, without losing functionality? An example is, I see a VCO where you patch in to change waveforms. It seems like wiring that to a switch would make sense, but then, I don’t know. I hope that makes sense, happy to clarify further. It’s safe to assume I want to switch between different waveforms, and have a sub oscillator I can mix in. Not saying that to get a walkthrough, but to give you more intel.

Thank you again. You all are patient and generous.

without seeing the design, it sounds like something along the lines of a rotary swtich would just take the place of the patch to select the desired wave.

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That’s what I suspected. Very cool, and many thanks.

Albert gave very little information aside from VCO’s VCF & i think EG. The video included in the link up top gives a lot of insight into signal flow that i’ll be using for inspiration for sure.

or bring each wave to a pot and mix them down into one signal, that would give you more control.

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Most of my builds are just gluing modules together, so for example I built the HAGIWO $9 VCO twice and instead of putting it into a module format I just used it as an oscillator for the synth feeding it all the requirements it needs from other sources instead of jacks. I took the outputs of both into a simple mixer with an added noise source (another building block) and that gave me one output to feed the filter input.

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Can you explain this some more please Craig. I understand having each signal sent to a different position on a selector pot as twinturbo suggested. Can you explain practically what your method does? In my mind it combines the waves’ signals, and you sweep between them? With different combinations? But that doesn’t make sense to me in theory or in practice. Sorry, this particular part has me very confused.

On another note, I saw your 16voice Poly on Facebook just now…wow, very very nice.

I’m getting a Thomas Henry book that should help me understand oscillators better, on a side note.