I spent 2018 getting started with synth DIY after about a decade of tinkering (some amateur, some professional) with electronics, programming and traditional instrument building. I don’t have much to add to what others have already said, but here are some pointers based on my experiences:
I initially got interested in building a eurorack modular system, but quickly realised that building an all-DIY rack from the ground up would be a long, difficult project, so decided to start of with something quicker and simpler. I built a Shruthi XT, which are discontinued but open source, with PCBs easily available from e.g. ModularAddict or Pusherman. This turned out to be a perfect first project — small and relatively cheap but immediately musically usable and surprisingly versatile for what’s inside. Here are some photos and notes on the build: https://waterpigs.co.uk/notes/4qt1Ap/ https://waterpigs.co.uk/notes/4smPUW/ https://waterpigs.co.uk/notes/4tWKPQ
If you build a Shruthi, consider installing the YAM firmware on it! It significantly improves the rather weedy saw and square wave oscillators in the official firmware.
I was so inspired by the Shruthi that I decided to build an Ambika (basically a 6-voice polyphonic Shruthi with better DACs and more programming options) before starting on a modular. That was a much more challenging project, but also definitely worth the effort, and my Ambika gets much more use than my Shruthi. Here are some photos and build notes: https://waterpigs.co.uk/notes/4uSCa6/ https://waterpigs.co.uk/notes/4uUASa/ https://waterpigs.co.uk/notes/4tkKf2/
When I finally started on a DIY modular, I began by building an Anushri, to complete the set of pre-modular MI synths, with the idea that it would be a good starting point for a system before eventually being replaced. This turned out to be true to a certain degree, but unless the anushri particularly appeals to you, I wouldn’t recommend it, and regret building it a little bit, especially as I didn’t follow my own advice and used cheap, wobbly pots on the control board. The anushri is very hard to get tracking V/Oct accurately, and despite the patchbay is not at all well adapted to fit into a larger modular system.
If I was going to start over, I’d probably start off by building: (micro)Braids (or Plaits, although there are fewer resources available for DIYing that), micro o_C, Streams/a similar VCA+filter+envelope/LPG, and an output module to get a nice compact, versatile single voice, the parts of which all remain indispensable as the system grows.
General DIY observations and important lessons learned:
- Don’t use cheap pots and encoders. Buy good quality, metal, bushed ones with threads, even if they cost 2x or 3x as much. It’s really worth it. If you’re willing to wait, you can get them cheap via group buys.
- Through-hole is nice to start out with, but with a good iron, thin solder, flux and desoldering braid, SMD is significantly easier, faster and cheaper — at least down to 0603 size and SOIC packages. 0402, TSSOP and very fine pitch ICs are a bit trickier. I recently built a couple of Befaco kits after working predominantly with SMD, and very quickly got bored of all the wire bending and trimming. There’s no way I’d build another Ambika now!
- It is possible to get many components cheaper via group buys and ebay/aliexpress, but it costs time and reliability. If an aliexpress seller says components are 1% tolerance, assume it’s more like 2-5%. Anticipate around a 15% failure rate where the supplier sends you completely the wrong thing, and will probably refund you, but the whole process wasted a month of shipping time. In my experience this is still the case with e.g. Digikey, but it’s more of a 1% chance.
- DIY is fun, but it takes a long time and is fiddly. Overall, it’s unlikely to save much time or money unless you’re in a position where you have much more time than money, and already have the tools available. It is, however, immensely satisfying and educational.