Here's a simplified Tube Screamer circuit from Run Off Groove, the Tube Reamer. Basically, it's a buffer-less TS without the tone control. The IC can be just about any dual op-amp. JRC4558 or TL072 are good places to start. Should be a great candidate for a 1590a build. For more info, schematic, and demo see the ROG site.
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.