Stumbled across this one over on the old La Revolution Deux blog. It's a simplified version of the Diamond Compressor, removing the EQ and the blinking LED circuitry. Makes for a much smaller footprint and will fit nicely in either a 1590B or 125B. Here's the schematic for reference.
This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.