DIY Analog Synth Looks Like Fun

The relative ease of building the individual components that make up an analog synth make it very tempting to DIY your own. That’s what [Albert Nyström] did and the result is this great looking, and great sounding, analog synth.

The VCOs in his monosynth are based around the AS3340 VCO chip, which is a clone of the Curtis Electromusic Specialties‘ CEM3340 chip (used in machines such as the Oberheim OB-Xa, the Roland Jupiter-6, and the Sequential Circuits Prophet-5 among others.) The voltage controlled filters are based on Moritz Klein’s VACTROL based VCF circuits, and the envelopes based on Thomas Henry’s 555 envelope circuits (Google searches will dig those up pretty quickly, as well as schematics for builds using the CEM chip.) Finally, the keyboard is a donor from an Arturia Keystep. While there are no step-by-step build instructions, or a schematic, we do have some info about the instrument. As you can see from some of the gut shots, it should be fairly easy to figure how [Albert] has put everything together. Or not.

Even if the internals are a bit wild, the end result is a great looking monophonic synth that does pretty much everything you’d need. If you feel the itch to wire a bunch of components together and make one yourself, there are messier ways to go about it. Or maybe you’d prefer to go the digital route? Either way, synths are a ton of fun to build and to play.

11 thoughts on “DIY Analog Synth Looks Like Fun

  1. I never built a synthesizer, but spent a lot of time decades ago trying all kinds of circuits. Not only did I learn new electronic things, but learned how instruments made their sounds.

    A modular synthesizer makes it easy to try things.

  2. This is fantastic! Great build, capabilities, and impressive demo. The article says it’s a monophonic synth. What happens when multiple keys are pressed simultaneously? What would it take to make it polyphonic? There were moments in the demo (first 5 min) where it seemed polyphonic, but perhaps that was the multiple VCOs?

    Well done! #labor_of_love

    1. There is only one key at a time to define 1 or up to 3 oscillators to do one thing. In the history of synths poly came much later and with digital techniques not a simple oscillator or 2 or 3 running in parallel. An organ can do poly but there is essentially one oscillator for every key and little of the filtering and ADSR etc, till the organ has even more circuits.

      Depending how this keyboard is wired two notes at a time would be the lower or higher note, or the resistive sum of the 2 notes “somewhere in between”. One note only.

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