Loving this PCB set. The module itself is a really characterful, dirty, noisy replication of early digital delay designs. The ENIG panel design with the exposed copper looks really good too.
It’s a (long) through-hole only build, with three sandwiched PCBS, but the build guide is very easy to follow, and there are completely documented schematics, which always make troubleshooting much less of a headache.
Some calibration is needed, but it’s really straightforward.
Almost worked first time – somehow I’d managed to fit a TL072 instead of a TL071, but it was easy to track down the problem.
The RAM chips used are quite obsolete now – there are duff copies flying around, so be careful. I got mine from an old 8-bit computer specialist – www.dragonplus-electronics.co.uk – no problems at all, so worth a shot if you’re in the UK.
You can buy them from Feedback Modules directly as well.
Take care handling the RAM as it’s meant to be very static sensitive.