MIDI DAC for Vintage Synth Hacks

A lot of classic synthesizers rely on analog control voltages to vary parameters; this is a problem for the modern musician who may want to integrate such hardware with a MIDI setup. For just this problem, [little-scale] has built a MIDI-controllable DAC for generating control voltages.

It’s a simple enough build – a Teensy 2 is used to speak USB MIDI to a laptop. This allows the DAC to be used with just about any modern MIDI capable software. The Teensy then controls a Microchip MCP4922 over SPI to generate the requisite control voltages. [little-scale]’s video covers the basic assembly of the hardware on a breadboard, and goes on to demonstrate its use with a performance using the MIDI DAC to control a Moog Mother 32 synth. [little-scale] has also made the code available, making it easy to spin up your own.

We can see this project being indispensable to electronic musicians working with banks of modular synths, making it much easier to tie them in with automation in their DAW of choice. This isn’t the first MIDI interfacing hack we’ve seen either – check out this setup to interface an iPad to guitar pedals.

7 thoughts on “MIDI DAC for Vintage Synth Hacks

  1. The most prevalent standard CV for analog synths is +/- 10v… I dont see circuitry to provide this range of voltages, so maybe it is only good for synths with a 0 to +5 CV… Which i guess maybe there is some of in existence? There are a few CV standards.

  2. … And the good thing about standards .. etc.

    I use 0-10v (actually 10.23v) for my MIDI – CV beast, which is switch selectable to be offset so it is +/- 5v instead. For oscillators that follow the 1v/octave “standard”, it gives full range control over the audio range.

    For a more complete MIDI-CV converter, you might consider generating a gate signal to trigger an envelope shaper or two, and you could do with more than one analog output – like for oscillator frequency, modulation, pitch bend and volume. There are another collection of “standards” for gate signals.

  3. So.. is the reason why they’re not using any DAC built-in-to the Teensy is because.. of the voltage swing? or.. is it speed? Forgive my ignorance, I know not much about USB HID devices and timing.. or the lack thereof when it comes to interrupts and the like.

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