Buchla systems use 1.2 volts per octave for pitch CV, not the Eurorack 1V/oct standard

The Buchla standard for pitch control voltage is 1.2V per octave (0.1V per semitone), derived from the original 100 and 200 series design. This differs from the Eurorack 1V/oct standard used by most modern modular systems. On a Buchla keyboard (218e), C at the lowest octave is 0V, and each higher octave adds 1.2V. When interfacing Buchla with Eurorack gear, a CV converter is required; the 225h module provides this translation. The 251e sequencer’s voltage display uses this same scale: 0.1V equals one semitone.

Examples

On the 218e, C4 = 2.4V; on a Eurorack system the same C4 would be ~4V (depending on reference). The 225h module provides 1V/oct output jacks for Eurorack compatibility.

Assessment

Given a Buchla pitch CV of 3.6V, identify the octave and note. Calculate what Eurorack CV would represent the same pitch.