EFM Synthesizers was located in Houston, Texas USA. EFM had been on the web since 1996 selling boards and kits to the DIY synthesizer community. The site includes schematics for ARP, Moog, Oberheim, Korg, and EMS-type voltage controlled filters, oscillators, amplifiers, and everything else you might need to build a modular synth.
This an archive keeping Tom Gamble's EFM work evolving.
EFM Users is for people that use electronics for making music. Synthesizers, computers, software, midi keyboards, midi modules, DIY electronics, guitar amps, stompboxes, transistor radios….ect are all legitimate topics.
EFM projects are for experienced DIY builders, because project often require mods to the PCBs, and documentation assumes a high level of electronics experience.
I just ordered the last available Wildcat PCBoard! One called it a Gnom on stereoids, we will see...
The plan is to lay it out as an semimodular synth (prepatched/normalled) with keyboard.
So here is the 28 pages thread about the widcat from the old forum. The most findings/mods/fixes come from