This is the legendary first edition Big Muff from the late 60's. Since the pots have been changed out with long shaft types it's impossible to pin down the specific date, however it does have the Fairchild 2N5133 transistors, which were believed to be used in the very first production units. The brown colored board is present in those as well, along with the absence of electrolytic coupling caps. It's believed that Jimi Hendrix bought one of the earliest versions, which leads you to believe it would have had the 2N5133 or 2N5088 transistors! Either way, the result is a tremendously good sounding pedal, which resembles a cranked tube amp moreso than anything else. Other than the changed pots the unit is all original. The long shaft pots used make the knobs stand out a little far from the unit, but everything still functions perfectly, as it should.

Here is a quote from the original pedal designer Bob Myer:

"The Big Muff was designed after analyzing the distortion units in use at that time. It is one way of getting sustain with acceptable distortion using diodes as soft limiters. I never thought at the time it would become so popular. It was not designed to Bell Labs standards, but I knew then what Mike wanted. Low cost and easy to build. At that time the Fairchild company had line of inexpensive plastic transistors that I was using at the (Bell) labs. I believe those are what I used in the first design (Ed - those were in fact Fairchild 2N5133 transistors). However I think the other component values had a much larger effect on the sound. The Big Muff generates harmonics of the input signal which are filtered by the circuit design and produce the differences in the sound." - Myer in 2010