GIN: A Drum Synth for the Original OP-1

A drum synth for the original OP-1

GIN is a drum synth I’ve built for the original OP-1. It’s based on the PO-32’s drum engine and puts 24 sounds across the keyboard, one on every key. It took ages to get right, but I’m happy with it now.

Two sounds on every key

Each key has an A and a B setting, and the blue encoder morphs between them, so a kick can go from tight to boomy while you play. The main controls sit on the encoders, with shift for the rest. I’ve kept the play screen as close to the original OP-1 look and feel as I could.

The engine goes deep, so T1 opens the Advanced pages. Page through them to edit all 21 parameters, including separate tone and noise envelopes. You can name each sound as well.

Eight kits to start with

GIN comes with eight factory kits adapted from CNTR RNDM’s free PO-32 kits, and each one fills all 24 keys. The original sounds are his. I’ve laid them out across the keyboard and added variations. His kits are on his YouTube channel and well worth a listen.

Edits to the working slot survive a restart, and holding a snapshot button saves a separate named preset.

What’s out today

Version 1.0.0 is a source release for community firmware builders, tested on the original OP-1 with firmware #246. There’s no loadable gin.op1p yet. The op1r plugin adaptor only covers the sample-based engine today, so GIN needs a new one for drum synthesis, and that’s what I’m working on next.

GIN plays four voices at once. Very dense patterns can still break up when a lot else is running.

It builds on op1r by pcppcp and contributors, and the synthesis core comes from Eric Lewis’s libpo32. Thanks to all of them.

If you’ve got a PO-32, PO-PatchStudio lets you design its drum sounds on your computer, free.

GIN is free too. If you’d like to support my open source work, you can buy me a coffee ($5), lunch ($10) or dinner ($20), or pick your own amount from $3. It doesn’t unlock anything. It just helps me keep building mods like this.

GIN is an unofficial mod. It isn’t affiliated with or endorsed by Teenage Engineering or Sonic Charge.

Get the GIN source on GitHub · Join in on the op-forums thread.