Volume only theremin schematic

Christopher,

not to derail the thread, but I want to thank you for the sharing of your endeavors. I don’t know if you’ve considered uploading your PCB designs to oshpark, but that might be a great way to germinate the theremin world with your efforts. These uploads are freely “shared” projects at oshpark and  anyone can order a small batch (3 PCBs is a typical minimum order). I think your “Clara” voicing is fantastic. It’s proved difficult to follow the path you took to get where you are (you had a tube mixer for a while, no?) but your most recent sound samples nonetheless indicate you have arrived at something special.

apologies to the OP for the off-topic conversation

no apologies needed!

BB & Phone,

Being everyone is friendly let me say all my theremin designs used a 1N914 diode for mixing. I discovered early on, bench testing, the sound I was after begins with diode signal mixing. Also the type of coil used had little to do with the sound. In the image below you can see what I used and my tube theremin had no thermal drift. I could adjust it to 300 hz and in the morning 10 degrees F cooler it was still humming at 300 hz +/- 10 hz.

The voice sound I like comes from having circuitry eliminate the third harmonic throughout the range. I had trouble reproducing the vocal effect until one day dewster showed me how to breakout the RF signal from a theremin board for better diode mixing and shaping.

Also I used solid state tuning on my tube design which I am surprised others never demonstrated, that is part U3 at the top of the boards below.

I always believed in building a theremin in a modular fashion so sections can be easily replaced with improvement.

Christopher