Weak Signal After Input Cap (DIY Tone Stack Troubleshooting)

[00Stevens]

I built this Big Muff Tone Stack to add to a fuzz pedal, but the signal is barely audible. http://tagboardeffects.blogspot.com/2013/08/bmp-tonestack-w-lpb1.html
I checked for solder bridges, and swapped the transistor (as a guess), but that didn't fix it. I poked around with an audio probe, and found that the signal is normal at the input, but immediately gets very quiet after the 4.7n capacitor. What does that seem to point to? Also, the voltages are about 5.2 at the collector, .9 at the base, and .12 at the emitter. And the only way i can get a faint signal at the output of the board, is to turn the trim pot completely counter-clockwise- which seems weird. I don't really know what to do with all this information, but  i'd appreciate any ideas of what the problem might be.

[duck_arse]

please be so kind as to show us photos of your build, both sides, if you would.

[00Stevens]

Not my neatest work...

[willienillie]

A few things.  First, I don't like the way that trimpot is implemented, though it should still get loud maxed out (CCW as you said).  Second, remove power and scrape between all those tracks on the back.  I use a dental pick type of thing.  I know it's mostly harmless flux, but there can be little bits of solder in there, potentially creating bridges.  Lastly, I can't say for sure, but it looks like the 100n in the bottom right of the first pic might be connected to emitter instead of base.



Edit:  After looking some more at your backside pic, that cap is definitely connected to E instead of B.  So that's your problem.  But still, scrape that flux, and maybe consider some modification (cuts/jumpers) that would swap "wiper" and "hot" pins on that trimmer.  CW vs CCW doesn't really matter.

[00Stevens]

Ahh. Thank you very much. I was so overwhelmed with all the stupid things i might have done wrong that i missed that. And with the trimpot- one way's as good as the next to me- i'm just gonna set it and forget it anyway. Thanks again. It was driving me nuts.