Today's layout is the EQD Plumes. It's based on the Tube Screamer but with a load of tweaks, including the usual BJT buffers replaced with op amp buffers, selectable clipping, and a charge pump to provide a bipolar supply. Should fit nicely in a 1590B.
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.