[sdiy] Polyphonic MIDI to CV

Brian Willoughby brianw at audiobanshee.com
Fri Jul 9 18:37:28 CEST 2021

What sorts of circuits are voltage-controlled in your project? i.e. What do the various CV signals control?

It's certainly possible to build a MIDI to CV circuit that handles more than the typical standalone MIDI-to-CV. As one example, the old Prophet VS has 60 CV channels inside. Do you know how many CV you'll need?

You don't really need CV to turn on each voice, but a simple analog switch. The problem with a switch, though, is that it does not impart velocity. If you want velocity in a top/divide then you'll need 128 VCA circuits to cover the full MIDI range of notes. If you don't have 128 VCA, then your full polyphony will be reduced to the number of VCA that you have.


On Jul 9, 2021, at 07:45, francesco mulassano via Synth-diy <synth-diy at synth-diy.org> wrote:
> Logan has top generator with dividers and BBD for the 'fx'
> Il giorno ven 9 lug 2021 alle ore 16:44 Oren Leavitt via Synth-diy <synth-diy at synth-diy.org> ha scritto:
>> What type of tone generation does this project use? Top octave generator/dividers were typical in many 70s string synths.
>> - Oren
>> On 7/9/21 9:09 AM, francesco mulassano via Synth-diy wrote:
>>> as a feature, however, I would really like to use the original scheme as much as possible and remain analog as possible (apart from midi, lfo and reverb)
>>> Il giorno ven 9 lug 2021 alle ore 14:14 Mike Bryant <mbryant at futurehorizons.com> ha scritto:
>>> Well I would suggest at least doing the midi through oscillators out in digital.  Definitely easier and cheaper as a single mcu will be powerful enough and is needed for midi anyway.
>>> -------- Original message --------
>>> From: francesco mulassano via Synth-diy
>>> Date:09/07/2021 12:17 (GMT+00:00)
>>> Hi, I'm thinking of creating a string machine starting from a project from the 70s. Basically, a replica of an analog string machine with new components. The tricky part I think is the full polyphony with the MIDI to CV conversion. There will be no keyboard in the instrument but there will be midi input connection.
>>> Do you have any idea, project that does not use commercial modules that would be impossible to implement in the circuit?
>>> Thank you
>>> Francesco

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