Hello Theremin World!
After playing around with building several toy theremins many years ago, I've decided to return to the hobby with a goal of building a quality playable instrument.
Given I'm in the software industry and already have Arduino coding skills, I'm drawn to using the OpenTheremin project as a starting point. However, I don't just want to buy a pre-assembled board, if for no other reason than I like doing things the "hard" way and want to learn, and have the ability to make custom changes over time. I have PCB-making skills and equipment. Also I hate SMD soldering!
So I'd like to design an OpenTheremin PCB for use with through-hole parts. I've seen references to others who have done the same and it seems straightforward, but can anyone point to any specific guidance or pitfalls on going this route? Specifically I'm wondering:
1) The only part in the BOM that doesn't have a through-hole version or close alternative seems to be the BB914 varactor diode, and I wasn't able to find another varactor/varicap with similar properties. Is the best bet just to use the SMD version here with a SOT23 to DIP adapter?
2) There is also no direct through hole equivalent to the SMD CC453232A inductor (1mH, 40 ohm) however there is a close match in the B82141A1105J000 axial RF choke (1mH, 33 ohm); any reason this substitution could not be made?
3) I see lots of references to board layout being critical to the OpenTheremin sound but without a lot of detailed guidance on what to avoid. Are there specific components that shouldn't be near each other on the PCB?
Any other tips/tricks on building a from-scratch OpenTheremin would be appreciated!