This is a Kosmo conversion of the NLC Bong0 twin t drum PCB. Or rather, two of them.
I did it as a dual module because, really, who ever heard of a single bongo?
The PCBs are mostly SMD — 0805 resistors and capacitors — my first substantial SMD project in several years. The diodes, the IC, and the headers are through hole. So are the panel components, when built as a Eurorack module, but of course that won’t serve for Kosmo.
Mostly. I did keep one pot on each PCB board mounted, to provide one attachment point for the PCB. A second attachment point is a spacer, secured to the panel through a hole and to the PCB by appropriating one of the holes in one of the unused jack footprints. (It’s connected to ground as is the panel, so it’s OK.) The other pot, the 1/4" jacks, and the LED (which was supposed to be blue but I forgot and used green) are wired to the corresponding footprints.
To avoid having too little space between knobs I wanted to offset the second board vertically, but doing so would have run into the jacks. So instead I flipped it upside down, and it worked out best to board mount the other pot on that board.
The two boards each have their own power header; I plan on making a two-headed cable for it instead of running two cables to two bus board headers. And I plan on being very careful because there was no room on the PCB for box headers, and because due to one board being flipped around, the two headers are oriented oppositely! Which is a fried TL072 waiting to happen.
Git repo for the panel Gerbers and build notes here: Richard Holmes / Dual Bong0 · GitLab