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As you'll see from my other threads I just finished one of these (though I'm still working on making it oscillate). I spent some time experimenting with it so I thought I'd share my findings.
Pinkjimiphoton recommended using leaky low gain NPN germaniums for this so I had a go after using a pair of 2n2222s which sounded good. I tried one low gain ge (50 hfe) for q1, and then q2, partnered with a 2n2222 but the thin setting was muffled and the fat setting wasn't fuzzy enough for my tastes. I found an ac127 that was around 130 hfe (medium leakage) and tried that with the 2n2222 and found that with the germ in q1 and the si in q2, the thin setting was sweeter and the fat setting was REALLY fuzzy and messed up - perfect! I biased q2's collector to 8.8v which is not what's recommended but I found that a lower voltage brought the tone into more mundane distortion territory. The thin setting I found a bit harsh in the treble so I added a 0.01 cap to ground with it which tamed it just fine.
if you put 2N2222 maybe try add a 5pf from base to emitter so you can lower the bandwidth of the silicon to be more like germanium. 2N2222 has < 2pf BE junction right from the datasheet if I remember correctly.
If you want to get REALLY wild with pedals with this topology, try something with a Hfe around 200 for Q1, and something around 40 for Q2.
That's if you dig the super blown out tone...which I do.
