Buchla - 225h MIDI-CV Interface

The 225h is a combination of format converters, CV-processors and a MIDI to CV interface. It's the perfect external Input Port into the Buchla system that integrates MIDI data as well as common analog standards into 200e compliant CV.

The left third of the module offers adapters in the form of three multiples. The lower two multiples are purely passive and are intended for audio signals. This module converts between Tini-Jax, 3.5mm jack and 6.3mm jack. The upper multiple converts between banana, 3.5mm jack and 6.3mm jack. This multiple is intended for control voltages. It contains an active circuit that suppresses negative control voltages, as these are not used within the Buchla system because they can lead to damage. In addition, a Buchla compatible pulse is generated via an additional Pulse output as soon as a rising edge >3.5V is registered.

The middle section offers three CV processors. Two of them are set to convert between the 1.2V/octave and the 1V/octave standard. The upper CV processor provides a combination of attenuator/amplifier and positive offset to scale CV signals and convert bipolar signals to unipolar CVs with an offset if necessary.

The right third provides the outputs of the MIDI to CV converter in the form of Pitch CV, Note On Pulse, Pitchbend CV, Modwheel CV, Velocity CV, Aftertouch CV, MIDI CC#4 CV and MIDI CC#7 Volume.