about the Big Muff and Rat circuits

Here, thanks to electrosmash.com, is a nicely-annotated schematic of the famous Big Muff distortion pedal.  This is often called a "fuzz pedal", but as you can see, at least according to my newly-developed definition of fuzz, this circuit is not it.  There is no adaptive biasing feedback path.  It's just a pair of cascaded diode clipping stages, plus buffers and tone control.  This comports with the fact that Big Muffs never seem to produce what I call the fuzz effect, although they definitely serve up plenty of thrashy distortion.

Same goes for the ProCo Rat pedal:

Again, no active feedback-biasing, just a diode clipper under the hood, driven by a fixed-EQ mid-boost stage.  I've heard people call the Rat a "fuzz pedal", but according to my definition, it is not any such thing.  I think these pedals are called "fuzz" just based on what I consider to be a misunderstanding, the notion that there is a single one-dimensional axis of "amount of distortion", and anything near the high end of the spectrum counts as "fuzz".  It ain't necessarily so!



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