bad gating on a Tonebender Mk II circuit

[mordechai]

I just built up a TB MK II circuit using 3 2SB54's -- I tested them on a breadboard version of the circuit before soldering them onto a PCB, and they are fine.  But the wired up PCB version of the circuit gates pretty badly.  I have a 100K trimmer on the collector of Q2 and adjusting it leads to tone and bias differences, so that's working...but no matter what position it's in, the gating is pretty substantial.  With the guitar volume full up, the tone is actually pretty nice and snarly, though it is a touch lacking in sustain.  When I bring the guitar volume knob down a bit, it totally peters out.  I have the resistor on the base of Q1 as a trimmer,  so I've tried it both in the 10K-ish and 100K-ish areas, and the problem persists.  Here are the voltages on the transistors:

Q1 E:  0.0
Q1 B: -0.05
Q1 C: -8.27

Q2 E: 0.0
Q2 B: -0.08
Q2 C: -0.24  (with the Q2C trimmer at about the halfway point, so about 47-55K resistance I'm guessing)

Q3 E: -0.13
Q3 B: -0.23
Q3 C : -0.13

I'm running the circuit off of a voltage inverter, with pin 5 giving off -9.36V.  There is a 100R resistor following this before the power goes into the rest of the circuit but I can't imagine that tiny bit of resistance is causing this problem.  Other than the trimmers I noted, it's a stock circuit.

Any suggestions?

[Electric Warrior]

There is something wrong here. Q3C should measure a lot higher than that. Once you figure out what caused this problem, the trimmer on Q2 should help you dialing out the gating.

[mordechai]

EW, I figured out the problem...the bag of 470R resistors I used was mislabeled (thanks, Tayda, so much...) and had a 470K resistor in there.  I replaced it with the proper value and bam, sounds great.

BTW, I built this using Toshiba 2SB54's (higher gains around 200Hfe, leakage was Q1=270mA, Q2=150mA, Q3=250mA) and it sounds astoundingly good.  It sort of "shines" and feels like the harmonics leap out even more than a build I did a few weeks ago with vintage OC82D transistors with similar leakage.  Those 2SB54's are really special.  I wonder how the 2SB56's are...

[mozz]

2sb54 2sb56, i see the specs as the same basically, 2sb56 were used as output transistors. but........in my Sams transistor spec book 2sb54 is gain of 74 @ 1ma, 2sb56 is gain of 80@ 50ma, but 2sb56 has twice the case dissipation, hence use as the output trans.