Built this up on a GGG PCB
Sounds really cool in the fuzz modes! Added a switch to bring C7 (4.7nF across E>B of Q3) which tames some harshness and mellows the highs, so essentially 4 different fuzz tones, and a treble booster.
The treble booster is quite harsh and barely starts at unity - so its really a boost.
I can see how this would benefit from some modern changes - ie change the esoteric treble boost to something more usable. But I wanted to build it to the vintage specs.
I added some of my own modern mojo - Bicolour LEDs for the modes, 9v DC power (original was battery only) and making it fit in a 1590BB.
This is going to go to a famous player for him to compare to his original unit for me and maybe make it onto his pedalboard - very excited!
Well worth looking into if you like your interesting fuzz tones.