Space Drum (from today's Patreon feed)

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If you have, I was able to get the unadulterated schematic for it. I might take a shot at this. I think I have a couple extra 13700s from my *- order.

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Eh who am I kidding. If someone else doesn’t lay out the PCBs and test it first I’ll probably be too sheepish to myself.

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nice. i was wondering why this thing would sound like at a pretty fast bpm. I’m planning to sample the audio onto my Sample to see what shenanigans I can get up to. not quite the same as the real thing.

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It doesn’t look too challenging (though I’m not about to try it myself.) I think the fact that it’s clearly laid out makes it easy to plan out subassemblies on veroboard or breadboard. When you have the layout for one part, move on to the next. Even without performing a final pass to integrate and simplify the wiring, you’d then be able to put the subassemblies together into a single wiring and layout plan.

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A bit of googling brought me to https://www.freestompboxes.org/viewtopic.php?t=11251 which has a somewhat more readable version of the 13700 schematics, and several comments from the original designer (including a scan of the original schematics from 1979).

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Seems you can simplify it quite a bit by 1) using a mikrokosmos for the input, 2) dropping the modulation bits in the upper right corner (that’s from the super space drum), and 3) using a dual supply, instead of the power supply bits. What’s left is two LM13700s and one LM358 (½LM324, or you could use a TL072 etc).

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I’ve built the Rakit synth drum (based on the Boss PC-2) which has a few more controls and you can trigger externally while tapping the piezo at the same time.

There are a few DIY versions of this.
It also takes a trigger AND pitch cv

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