I started following the Look Mum No Computer YouTube channel recently, as well as the Look Mum No Computer but more serious ish channel. Sam Battle’s a wild and weird guy, as is probably anyone who’s ever built a Furby organ, and his methods are not my methods, but he’s a great proponent for seat-of-the-pants, rough and ready DIY modular synthesis. There’s a Discourse group for his synth-building fans (and him), which is small but I find it a lot more entertaining, at least, and more community-building than that other forum I don’t even like to mention the name of.
LMNC doesn’t go in for Eurorack: too “small and fiddly”. Instead he’s using what he calls the Kosmo format, though he says others have previously called it “metric 5U” (but a quick Google search for that seems to turn up only LMNC results). Panel size is 20 cm high by multiples of 2.5 cm wide. Jacks are 1/4″. Voltage levels and power connectors are the same as Eurorack, which is pretty convenient for both building and (co-)operating.
LMNC so far as I know is the only vendor of Kosmo modules, in board-and-panel form, and to date there are four on the market: A VCO, a filter, an LFO, and an ADSR envelope generator. Clearly you’re not going to build much of a synth out of those, though more are promised to come, but if you delve into the videos and into the forum you’ll find a lot of other modules Sam and other people have made, very often on stripboard with layouts provided.
It’s all an interesting contrast with the Eurorack community and market. Very brash, very energized. Might go places. Might crash and burn. We’ll see.