This final Ram's Head revision produced a more open, mid-forward sound with plenty of gain, pushing the pedal closer to distortion than traditional fuzz. While there are minor variations throughout this period, with some versions offering slightly more low end or a touch more brightness, the overall character remains remarkably consistent.
One thing I find especially interesting is how clearly you can see the circuit evolve during this period. The brighter, more open 1976 design gradually develops into the 1977 and 1978 Black & Red Muffs, which would eventually lead into the 1979 to 1984 Reverse Logo Muffs.
There were also several transistor substitutions during this time, including the 2N5087, 2N5088, and BC239C. However, because of the circuit design and surrounding component values, these changes had relatively little effect on the core tone.
Many players will recognize the sound of the 1976 Big Muff because one of the most influential guitarists of the 1990s built his tone around it, J. Mascis of Dinosaur Jr. You can see J.'s original Ram's Head Big Muff in the photo above.
As of today, I have documented more variations of the 1976 Big Muff than any other year. Most are very similar in sound, with only subtle differences between them, so rather than go through every version individually, I will give an overall description of how they differ.
The early versions are very representative of the J. Mascis sound, with an open overall tone and a brighter, more aggressive gain character. They cut extremely well in a mix and have a distinctive fuzz and distortion quality.
As the 1976 pedals progress, capacitor changes begin adding more low end, giving the circuit a fuller tone and fatter fuzz. These changes provide a clear transition into the Black & Red Muffs that would follow in 1977.
My favorite 1976 versions are these later circuits. The added low end gives the fuzz a fuller, thicker character while still retaining the open tone and aggressive gain that define the 1976 Big Muff.