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.

6 comments:

  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.

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  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!

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

      https://www.diystompboxes.com/cnews/mods.html

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