I’ve seen many Big Muffs listed with incorrect production years. In most cases, this is no fault of the owner, as dating these pedals can be difficult.From what I understand, Electro-Harmonix purchased potentiometers in bulk and stored them together in large bins. Whenever pedals were assembled, workers would simply grab the pots needed. If a large batch of pots was purchased in 1969 and another batch in 1970, the newer stock would be added on top of the older ones. As this process continued year after year, it was entirely possible for a pedal assembled in 1975 to end up with a 1969 potentiometer that had been sitting at the bottom of the bin.
Because of this, pot codes alone should not be relied upon to date a Big Muff. Over the years, after examining and documenting countless examples, I’ve developed a slightly different approach. While I do take potentiometer codes into consideration, I also place significant emphasis on the components, circuit board, and overall construction of the pedal when determining its production period.
The information presented below is based on the many pedals I have personally examined and documented over the years. As with anything related to vintage Electro-Harmonix pedals, there are always exceptions, but I hope this serves as a useful guide for identifying and dating vintage Big Muffs.
Versions
As you go through each year, I will list the pedal descriptions by year and version. The version numbers are for my own cataloging purposes and are assigned in the order that I found, traced, and added each circuit to my database.
These version numbers are not official Electro-Harmonix designations, but simply a way for me to organize and document the many variations I have encountered over the years.