Need help debugging DIY Blues Driver

[nobodysweasel]

Hello everyone. I finished putting together a DIY Blues Breaker several hours ago and it's driving me completely crazy. Usually I can get through the dubugging on my own, but I think I'll need some help on this one. I used the layout from tagboard at http://tagboardeffects.blogspot.com/2013/03/boss-bd2-blues-driver.html. It currently works fine when bypassed, but doesn't get any signal when engaged unless the gain is cranked all the way up, at which point it outputs a loud very ugly distorted signal only when the guitar is strummed hard. It's like there is a threshold, where no signal gets through below it, but is suddenly very loud and unpleasant when that threshold is crossed - but there is guitar signal getting through. Unless I've gotten things mixed up, I followed the layout exactly and did not substitute any components. I've checked every component, every wire, every solder joint probably at least 5 times. I don't have pictures at the moment, but I can post some tomorrow if that would help.

I found a previous thread debugging this circuit here: https://www.diystompboxes.com/smfforum/index.php?topic=109396.0. The schematic was posted in that thread as well (link here: https://www.dropbox.com/s/cgqxq82ze0xvjf3/Schem_AudioPath.pdf?dl=0). The OP of that thread, after getting his issue resolved, posted these voltages:

Q1: G - 4.57 S - 5.89 D - 8.73
Q2: G - 5.58 S - 5.89 D - 9.39
Q3: E - 9.39 B - 8.74 C - 5.60
Q4: G - 4.25 S - 5.54 D - 8.87
Q5: G - 4.70 S - 5.54 D - 9.39
Q6: E - 9.39 B - 8.87 C - 4.71
Q7: E - 3.63 B - 4.03 C - 9.39

IC Pins:
1 - 0.16
2 - 4.67
3 - 4.46
4 - 0.002
5 - 0.16
6 - 4.67
7 - 9.39
8 - cycles b/t 0 and  -0.2 mV

Here are my voltages:
Q1: G - 4.58 S - 5.32 D - 8.74
Q2: G - 5.19 S - 5.32 D - 9.38
Q3: E - 9.38 B - 8.74 C - 5.19
Q4: G - 4.25 S - 5.68 D - 8.98
Q5: G - 9.15 S - 5.68 D - 9.37
Q6: E - 9.37 B - 8.98 C - 0.21
Q7: E - 3.70 B - 4.07 C - 9.37

IC Pins:
1 - 0.14
2 - 4.68
3 - 4.46
4 - 0.002
5 - 0.14
6 - 4.68
7 - 9.37
8 - slight variations, very near 0

From what I can tell, my main issues are the gate of Q5 (way too high), and the collector of Q6 (way too low). The other voltages are similar to what I expected (but maybe these minor variations are significant?). I've checked everything in the circuit around Q5 and Q6 very thoroughly and it looks like everything is correct. I admit that I don't have a good idea of what the circuit is actually doing here, so I'm not sure what's going wrong. Does anyone have any insights that might help me figure out what's going on here?

[garcho]

Vero is evil. Yes, I know, many people have success with it. Many people don't. I know this is anecdotal, but I feel like a huge chunk of "why doesn't it work" threads involve a vero layout. Mixing things up while flipping the board over to do the trace cutting, and little shards of copper bridging traces, seem to be common culprits.

maybe these minor variations are significant?

No, they're not. You're right, Q5 gate voltage is too high and Q6 collector voltage is too low. Could something be shorting out at the gain pot? A lot of wires are crammed into that dual gang pot. Q5 gate and Q6 collector are coupled by C10 and both are connected to the gain pot, and both are the wrong voltages. You also mention cranking the gain, one more coincidence, so I would inspect that crime scene with a magnifying glass.