via Modular Experiments
"One feature I wanted to add is a row of analog inputs so that I can trigger the voices with external signals from my modular and sequencers. I tried unsuccessfully to find a circuit that would have a low-parts count and be relatively simple, not require ICs or rare parts, etc.
Eventually, I asked a manufacturer of Euro-rack modules if he would be kind enough to share his method for developing an appropriate trigger pulse from just about any external gate signal. He did not say if this was an original design or an adaptation of some other drum synth's circuit, but either way, it is not my own and I very much appreciate his assistance."
