RnFR wrote:why, because it's got a differential amplifer? i'd say the two have MUCH more that is different than they do alike. you would hardly be able to modify a superfuzz into an FZ2, you'd be much better off just building one from scratch.
Because in my opinion the business end of the FZ-2 - the octave and clipping section - is pretty much identical to the Univox, and the voicing of Fuzz I is similar to the notch switch on Superfuzz, only with a higher notch frequency and a little more treble rolloff. Then BOSS added the Fuzz II channel with a different voicing, the (maybe superfluous) Boost option, and a pretty nice tone section. Is this really enough to turn "super" into "hyper"?
I agree you cannot easily mod the Superfuzz into an FZ-2, but to mod an FZ-2 into a convincing Superfuzz all you need to do is change one resistor and one capacitor, jumper another resistor, cut another capacitor, and move the level pot and output to the 1k resistor after IC1a. Then change the diode clippers, and you should be good to go.