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DIY Black Star Theremin

Posted: Tue Feb 19, 2019 4:31 pm
by Dominique
I recently converted an old philips vacuum tubes radio into a theremin. A theremin is one of the first electronic instrument. It have 3 RF oscillators and 2 antennas which are parts of the tuning tank of 2 of the oscillators. One antenna is used to control the volume, the other one controls the sound. So yes, it is an instrument we play without touching it. It is at the same time very easy to play, and almost completely impossible to play.

This project have an unique feature: as the original radio was quite big, I didn't wanted to have it in my way when playing, so I decided to separate the antennas from the device. It is why I choose to use the Clapp oscillator. With it, the capacitance of the coaxial cable between the antenna and the electronics is in parallel with other capacitances of the circuit and become almost negligible, which allow to use cables of different lengths.

The whole development and construction took me more than 3 months, and the result is a very playable instrument with a good linearity on the antennas and a lot of different sound settings. Its name, the Black Star Theremin comes from a very funny border collie named Star. I put the documentation with the schematics on github: