Author Topic: Yet another Opamp Big Muff  (Read 2128 times)

DiscoVlad

Yet another Opamp Big Muff
« on: January 05, 2011, 05:05:31 PM »
This is my first build of 2011, and it worked first time... here's to a continued 100% success rate  :icon_mrgreen:

This is basically the same as the V4/V5 opamp Big Muffs from 1977/78 and has the tone bypass circuit onboard, instead of christmas tree style like the originals. I've also added polarity protection (in the form of a Mosfet/Zener) which the original didn't have.

Outside:



Insides:



It fits into a 1590bb, but is a pretty tight fit. Resistors are all 0.25W Metal film, Opamps are just whatever 741/4558 were cheapest.
Wires have been hot-glued for strain relief, and there's nomex paper (offcuts from work) underneath the board for insulation. so hopefully it should be robust.

Schematic Here
Eagle files and Board transfers here these are a newer revision than from what I built, and have a couple of components resized (all resistors and diodes are 0.3" pad spacing now).

This thing absolutely nails the Smashing Pumpkins - Siamese Dream guitar tone, and the first comment from my local music shop's guitar guy was that it sounds like a Guild Foxey Lady ??? I don't know either... It does sound great for fuzzed out bluesy solos, and thick grungy riffs though.

John Lyons

Re: Yet another Opamp Big Muff
« Reply #1 on: January 05, 2011, 08:39:00 PM »
Looks great!
Basic Audio Pedals
www.basicaudio.net/