CalTrans can be used to fix calibration of v/oct signals to oscillating sources - So now you can sequence your non-tracking filter or quirky oscillator!

Programmable Volt/Octave CV calibrator and transposer

  • Four V/Oct processing channels, each with
    • Curve correction and range expansion for any VCO, VCF or other oscillating circuit with a CV acting on pitch
      Works with other range systems (e.g. Buchla)
    • Switchable semitone quantizer
    • Adjustable portamento time
    • Adjustable glissando time
  • Separate semitone and octave transpose click-encoders
  • Inputs cascading with no added load for stable pitch control
  • Four user presets storing transpose, portamento and glissando
  • Storage of the calibration profile for each channel
  • Maximum voltage range covering 10 octaves
  • Presets, calibration and current state retained over power cycle
  • Volt/Oct inputs factory-calibrated in flash memory
  • Easy firmware update via a simple audio file
  • High-quality push-encoders with metal shaft
  • Skiff-friendly & compact module

CalTrans solves issues encountered when playing tonal music with a modular system: tracking problems, curves unrelated to Volt per octave ratio, limited octave range, cumbersome transpose,  Caltrans corrects and expands the range of troublesome VCOs and brings V/Oct tracking to anything that oscillates.  Besides calibration, the CalTrans offers live play features. Each channel can be quantized and any combination of them transposed jointly.  A pair of rotary encoders with detent allow an precise selection of octaves and semitones.
VCOs whose tracking doesn’t go high enough to follow the leader will see their pitch repositioned in their highest possible octave so that the global harmony is unaffected.
You can add a pinch of portamento and glissando to each channel and save the whole in user presets.


  • Width: 6hp
  • Depth: 36mm
  • Current draw: 39mA @ +12V, 8mA @ -12V

Caltrans Manual