Seymour Duncan Dirty Deed

Here's a pretty interesting distortion from Seymour Duncan. 2N3906 transistors for hard clipping and a two band gyrator EQ section. Originals I assume are all SMD and use MC33178 ICs, which I believe are equivalent to the LM833, but other dual opamps should work fine. Schematic here. Should be able to squeeze it in a 1590B with small profile jacks.

Seymour Duncan Pickup Booster

The Seymour Duncan Pickup Booster offers 25 dB of clean boost with flat EQ (and it's also a line driver). It uses a combination of two NPN and one PNP transistor. Originals use BC107s and BC177s, but other transistors should work fine as well. Check out the demo video below for more info.