Do voltages sent to the control inputs of the Shruthi analogue/filter boards correspond to any CV/Gate standards? Just ordered PCB and parts for an IR3109 filter, and was wondering if I could potentially use it, or the SMR4 filter as a standalone device, under CV/gate control.
The digital board sends an oscillator signal (not a mere CV for an analog oscillator) ; and pre-mixed, digitally generated, CVs for envelope and cutoff. Since the envelope is computed in the digital domain, there’s no need to generate a Gate signal. Moreover, modular stuff works with supply voltages greater than 5V (usually 12V or 15V), and the 1V/oct standard doesn’t make sense on a 5V scale because this would limit the range of everything to 5 octaves. The Shruthi works with 0.46875V/Oct, so the whole MIDI range (more than 10 octave) is contained within a dynamic range of 5V.