[found] a nice article on analysing Fuzz Face circuit (by William E. Overton)

[yeeshkul]

here http://etd.gatech.edu/theses/available/etd-04102006-123628/unrestricted/overton_william_e_200605_mast.pdf.pdf

and it includes a Spice model of AC128, yeaaaaah  (i won't copy it here as i am not sure if it would be polite to the author. Please just go through the article first)

[petemoore]

n  That's actually pretty cool !
  Digital Fuzz Face...I never got down to the bottom of it though...to see how it turned out...lol.!!

[Auke Haarsma]

well, to me it seems like a lot of copy / paste from RG Keen (which the author mentions btw) and an attempt to model the FuzzFace. I'm not really impressed at all.

[snap]

http://www.diystompboxes.com/smfforum/index.php?topic=46733.0

[mac]

Check this also:

http://www.diystompboxes.com/smfforum/index.php?topic=50712.0

http://geocities.com/guitarfxs/docs/fuzzface_dc_bias.pdf

and download this:

http://geocities.com/guitarfxs/exes/biascalculator.zip

enjoy,

mac