1 volt per Octave Calibrator

  • Analog oscillator calibrated to provide 7 exact steps in controlled voltage
  • Used to assist in calibration of tuneable VCOs for hardware and modular analog synthesizers
  • powered by a +/- 12V to +/-15V power supply from the synth under calibration
  • Circuit designed by Ray Wilson of MFOS.

  • calibrator-1

The next few synthesizers in my project list require special tools to assist in calibrating the oscillators. In the world of analog synthesizers, temperature, time and quality can effect the sound of a synth. Specifically, they need to be tuned much like a piano. Instead of loosening to tightening or replacing strings, analog synths require adjustments to the oscillating portions of their circuits or they may even need components replaced. The concept is that I can use this tool as a measured voltage source, stepping through the voltages 1v then 2v, then 3v up to 7v to ensure my synthesizers are tuned to 1v per octave. Therefore, I should be able to calibrate my synths to 7 octaves. You could also calibrate by  ear using a tuned piano or tuning fork. You can even use another synth with a MIDI to CV adapter and electrically measure key by key to ensure calibration. But I though this method actually makes it easier to calibrate on the workbench.

Again, using my concept of “things are not what they appear to be”, the circuitry is hidden inside a rather attractive little cigar box.


back to Synthesizers main.