Doepfer A-178 Theremin Control Voltage Source

Theremin module for generating a variable control voltage by approaching/removing hand to/from an antenna. The distance range is about 30-40 cm. Additionally the module is equipped with a Gate output with adjustable threshold level. Controls/Inputs/Outputs: antenna input, offset (knob for zero adjust), 2 x CV out, 2 x LED (for CV control positive/negative and zero offset adjust)
To simulate the original Theremin two A-178, a VCO (e.g. A-110) and a linear VCA (e.g. A-130 or A-132) are required. But of course the A-178 can be used to control other functions in the A-100 (e.g. filter frequency, modulation depth and/or speed, tempo, attack/decay time and so on).
The CV output voltage of the A-178 can range - according to the setting of the front panel controls - from -10V...+10V. The gate output switches from 0V to about +10V.

For more detailed information please look at the English user's manual A178_man.pdf

Applications:

• controlling any voltage controlled parameter of the A-100, e.g. pitch or pulswidth (VCO A-110), loudness (VCA A-130/131/132), panorama (A-134), filter frequency or resonance (A-120/121/122/123), phasing (A-125), frequency shift (A-126), resonance peaks (A-127), envelope parameters (A-141/142), tempo (A-147)
• triggering of A-100 activities via gate with adjustable threshold, e.g. starting an envelope (A-140/141/142), Start/Stop of a sequence (A-155), any switching function (A-150/151)
• Conversion into MIDI control change messages is possible with the  A-192.
  

Remark: If two or more A-178 are used the distance between the modules/antennas should be at least 40-50 cm. Otherwise the antennas may affect each other.

Technical Notes:

It's not possible to connect the antenna via an additional cable to the antenna socket or to replace the antenna by another element. Antenna and hand form a variable capacitor with a very small capacity in the pico Farad range. The electronics of the module is puzzled out just for this capacity range. If a cable is added or the antenna is replaced by another element the capacity range changes totally and the module will no longer work ! But it's possible to mount the complete module with antenna at the desired position, e.g. into a small case that holds one or two of the modules. It's also possible to use a longer bus cable to connect the module to the A-100 bus. If you are not able to manufacture such a cable yourself we may offer a suitable cable upon request. Please tell us the desired length for a quotation of such a cable.

Width: 8 HP / 40.3 mm 

Depth: 40 mm (measured from the rear side of the front panel)

Current: +60mA (+12V) / -20mA (-12V)