Well, good news folks!
I have it on the breadboard right now, and it pretty well emulates what the original does. Instead of Russian transistors, I pulled out some Japanese 2SB172's instead. Call it the "Nippon" instead of the "Sputnik". Anywho, they're all 0.03mA or better leakage-wise, 72 in Q1, 82 in Q2, and 80 in Q3 for gain. The voltages are more or less aligned with the original, +/- 0.1 of a volt here or there. I'm attributing the slight variance to the fact that I didn't have any 475K resistors, so I have 470K's in there right now. Instead of two 10K's below the CALIBRATE pot, I used a single 20K. Also, on the high filtering, a 472 cap is filling in for the 502 while I wait. The 243 CALIBRATE cap is being temp'ed by a 273.
As for the unknown JFET, I tried a 2N5457, 2SK30Y, and a 2SK30GR. As for the Ge diode, I tried a 1N60, 1N270, and a Russian D9E. The combo of the 2SK30Y and D9E gave the best performance when it came to setting the edge of oscillation, and the best decay as well. Funny, I was singing the praises of the D9E earlier today, and once again, it didn't disappoint. My source and drain voltages are a bit higher than the original when the gate is set at 6.26v, but again, I'm attributing this to the missing 5K at the B-C of Q1. Once my order comes in, I'll be able to tweak it some more, and retest the voltages.
I'm almost positive that the BS170 that's just below the unknown JFET is used in conjunction with the Mill bypass to switch the JFET off. Otherwise,
I think the oscillation would bleed into the audio in bypass. This is my theory, but it would be cool if some one with more brains on this could confirm.
All in all, pretty fuzzy, and when you kick in the DRIFT (oscillation), you can get all sorts of textures. The filtering is pretty cool as well. With the DRIFT off, at lower settings, it can be discreet. At higher settings, more effective. With the DRIFT on, freakin' awesome. Tone-wise, it's similar to the original, but the stand-in values, as well as different transistors, give it a different flavor. Say... a bit crunchier.
I'll audition some Russian transistors as well. I've got lots of them. The 2SB172's do sound pretty rad though.
More to come....
