Its not totally quiet, but it isnt as loud as Id expect, and swapping out diodes for clipping doesnt make any difference in tone? Any ideas? I made it to Mayo specs, and tried both bc550 trannys, and the 2n5088 with the same results. Pulling the Q3 and Q4 causes no difference in sound, but pulling Q1 and Q2 make it go silent, Test everything on the multi meter and it looks like power is going everywhere, including Q3 and Q4?
What are your voltage readings for the transistors?
I would double check your resistor values for R13-R16 and R20-23, too. One incorrect value on any of these might cause a significant drop in volume or fuzz.
If you can pull Q3 and Q4 and it doesn't effect the sound, I'd guess that they aren't amplifying. +1 to what Bean said, but you should also confirm that their emitter resistors (R16, R23) have good continuity to ground. Maybe reflow those joints.
Been busy at work, ill get the readings on the transistors tonight when I get done. I wired up another one and got the same problem?
Which version of the MB are you working from?
the latest one, and I made a Mayo and a Violet rams head.
Okay, we'll need some transistor voltages and maybe a pic of the top of the board to go any further, I think.
Ok I got around to doing this finally, using the Violet ramshead specs, with 2n5088s the trans are reading
q1, e 0.02, b, 0.56, c, 3.77,
Q2, e, 0.04, b, 0.64, c, 4.03,
Q3, E,1.10 , B, .065, C, 3.75
Q4, E, 1.00, B, 1.59, C, 4.48
Diodes reading 0.54 on d1 and 2 and 0.60 on d 3 and 4.
If I switch the q 1 and q2 around the Collectors are getting over 7.35v a piece on each with no change in volume.
Apologies up front, because I'm not gonna go downstairs right now and check my own VRH. Maybe tomorrow morning. But I can tell you that your Q3 voltages must be off because you need to have a higher voltage on your base than your emitter for an NPN transistor to amplify. Triple check R14, R15, R16, R17.
Okay, bright and early with the multimeter, from my VRH with 2n5088s:
Q1 E: 0.04, B: 0.64, C: 4.00
Q1 E: 0.05, B: 0.67, C: 4.28
Q1 E: 0.04, B: 0.64, C: 3.97
Q1 E: 1.23, B: 1.83, C: 4.90
That's with probably about 9.5 from the wall wart. I stick with my previous assessment: your Q3 voltages are off, and you've probably got a bad resistor value in that general vicinity.
I flipped the Q3 and it worked? Its still mildly quiet though. I guess maybe because its germanium and my band sounds like a macktruck.