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.

Thursday, December 5, 2019

Discrete Distortion +

I've seen a few people playing around with discrete opamps in classic circuits, and thought I'd give it a go with one of my favorite circuits, the classic MXR Distortion + (or DOD 250, etc.). The typical 741 opamp has been replaced with Joe Davisson's Diode-Compression Opamp. The 6.8k resistor in the bottom left corner of the board may need to be adjusted till the collector of Q3 is around 4.5v. I haven't tested this, but it should work.


  1. que interesante¡¡, ¿tienes idea si es posible reemplazar los 2n5087 por BC557 o 2n3906?, ¿la ganancia del transistor debe ser superior a 200hfe? gracias por subir el aporte, hace tiempo buscaba algo así.

  2. With germanium diodes the tone is great, but the volume is a little low. With 4148 the volume is much louder, but the tone is not so cool. Any suggestion? When I set the 6k8 resistor to 4.5V on the Q3 collector, the gain pot stopped working. With 6k8 everything worked normally. Great layout, as always! Thank you!

    1. There are several things you could do. Start here:

    2. That link was incredible. Can't believe I didn't run into it earlier. Thanks a lot for everything you do here.