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.

Tuesday, December 17, 2019

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.


  1. Hii . . .
    Why transistor can make sound clean, overdrive and distortion?
    Sorry its stupid question 😀

  2. Verifed.

    I used some LM833's as suggested, and got within 4% of the precision resistor values. The net result is at least close to the demo video: a hard rock/metal distortion with focused mids and a useful 2-band EQ. The sound can seem tight to the point of being stiff, but that might be a good thing in a band mix.