Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Mictester's Really Cheap Compressor (RCC) can live without a compression indicator. However, there are situations when such a tool would be helpful.

I had made a similar indicator for Merlin's Engineer's Thumb compressor, but unfortunately the approach used there could not be directly conveyed to the RCC without substantial overhaul, which would conflict with the whole idea of simplicity.

Minimalistic approaches for an indicator, as frequently suggested, like just tacking on an additional LED or even an additional transistor somewhere indiscriminately can have disastrous side effects, where simply "not working" or "being useless" are the most benign ones.

I made a circuit that is based purely on CMOS gates, a technology that goes back to John Linsley-Hood, a well known HiFi-guru back from the 80ies. It fulfills all demands I had for such an embellishment, technically and functionally. It came out really well and supports Mictester's "minimal parts count" ideology for the RCC.
A single bi-color LED lights up the green part in idle mode and red when compression kicks in.

Find an extensive description of that all on my web pages (http://me.aquataur.guru/musicstuff/compind_RCC.html).