Adding Patch Memory to Vintage Synths

[mamero]

I've been reading about various mods on vintage synths. It got me thinking. Are there any mods or kits to add patch memory to vintage synths? I have an ARP Odyssey and a Pro-One that would be amazing with patch memory or some kind of recall. Does something like this exist?

[acreil]

The Sequential Circuits Model 700 does that, sort of, but only by using its own envelope generators in place of the ones in the synth.

Beyond that it's not really a workable idea.

[The Real MC]

Adding patch memory to a synth is a LOT of work, no such kit exists. All the controls need to be under digital control and it takes a LOT of modifications and additional circuitry. Every single switch has to be replaced with a CMOS switch controlled from a logic demux system. Every single pot is a passive resistive element that is part of the circuit, and to implement digital patch storage those pots have to be replaced with an ADC so the micro can read them then a DAC with demux and S&H for control voltages back to the original system. Some serial resistive controls like filter resonance must be replaced by an OTA circuit. Plus the power supply needs to be beefed up to handle the new increase in current demand with all this new circuitry. All this easily doubles the component count and is not likely to fit in the existing chassis.