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Thereminator 1



Theremins are musical electronic instruments, played by moving hands around a pair of antenas : one for pitch, one for volume control. The sound produced is the result of the interactions of two HF oscillators. One fixed, the second one controled by the pitch antena. Here are some informations on the one i have builded

The Thereminator1 is based on the TECI 67/74, sligthly modified. This schematic come from the "Popular Electronic" article published in 1967.I have replaced all transistors and fets by common european references, the TIS58 is now a BF245... It is a discrete solution. I have used two big air variable capacitors instead of usual miniatures ones.They are for coarse tuning, 2 big buttons on in the middle of the front panel. Small knobs, on each sides, are for fine tuning.

The  power supply voltages is a clean +9V DC, a battery will work well too. Antenas are made with 2 bars of plain steel mounted on isolated jacks.The audio output level of the Thereminator1 is very very low ! It require a good guitar amp or a quiet mic/line preamp to drive it....Bandwidth is around 80..100Hz to more than 20kHz.

Points i have also noticed :

  1. The thing will not work at first time. It seems to be usual for theremin builders..
  2. The pitch antena is rather easy to tune, the volume antena is hard to tune...
  3. The thing drift "a little bit" with the variations of temperature and certainly some other factors..


It is a working prototype... Well tuned, It produce this very typical and unique sound. I have assembled it during summer 1996, more by curiosity than to build a real instrument...Today,  i admit it represent one of my favorite synths. May be one day i will build another one, with a "serious" output at +4dB and CV outputs...

Thereminator sound (mp3-173ko) 
The background sequence is played by an analog synth....




© Marc BAREILLE 2003,2004