Fuzz Face debug

[nobodysweasel]

I just built a fuzz face, and it's giving me problems (surprise).  It's the NPN silcon version from GGG.  I etched my own PCB from their image.  I included all optional parts.  The only substitutions I made were the transistors - Q1 = 2n5088, Q2 = 2n2222.  Oh, I also didn't have a 0.01 cap, so I substituted two 0.018 in series.  I previously breadboarded the whole thing, so I'm sure my substitutions work and the circuit is soild.

Now, this would normally be the part where I post voltages, but that's the problem - I'm getting no voltage at all to my circuit.  I'm using a one spot DC adapter.  When I check the adapter, I get ~9.5 V.  When I plug the adapter in and check the pedal's DC jack I get 0.0 V.  I swapped out the DC jack with another (testing it first, got 9.5 V), but that didn't change anything.  So does anyone have any ideas?  I've been thinking about it, and I can't come up with any reason why I wouldn't get a voltage reading at all at the DC jack....

[nobodysweasel]

Forgot to mention something.  Of course, the pedal does nothing because it has no voltage (no sound, no LED).  But it also doesn't let any sound through when it's bypassed.  I thought this was a bit odd - shouldn't true bypass still function even if the pedal isn't getting any power?

[Jdansti]

Could you post a photo of your power jack and bypass switch wiring?

[JustinFun]

Sounds like something's getting grounded - have you checked continuity to earth from the 9v pad, in and out pads with a multimeter?

[nobodysweasel]

Thanks for the responses.  I've made some progress, but I'm still struggling with some things.  Here's the update:

First thing, D3 was in backwards.  It wasn't labeled very clearly in the diagram, so I wasn't even thinking about it when I installed it.  Oops .  After that, it was still behaving badly, but suddenly the LED lit up and I had voltage at the DC jack (so I think it was grounded somewhere and I accidentally fixed it).  Unfortunately, it's still not working properly.  The only sound I get out of it is sort of a crackly hiss (which gets worse when the gain pot is turned up, and gets louder when the volume pot gets turned up - both somewhat encouraging).  I've checked just about everything I can think of for continuity, but I'm still at a loss.  I was finally able to measure some voltages.  I'll list them here, with the GGG listed voltages in parentheses:

Power Supply - 9.54 (9)

Q1
C - 1.15 (1.4)
B - 0.57 (0.6)
E - 0.0   (0.0)

Q2
C - 4.61 (4.5)
B - 1.18 (1.4)
E - 0.64 (0.8 )

Those all seem to be in the right neighborhood, but I'm not sure how close they need to be.  My Q1 collector and Q2 base are the furthest off, but I don't know what that means or if it even matters.

Any other guidance would be much appreciated.  I've been at it for like 4 hours straight, and I don't really know what else to try.

[nobodysweasel]

I realize this thread has mostly just been me talking to myself, but I figured everything out and I wanted to post an update, just in case anyone cares.  It all came down to two problems (well, besides the backwards diode I already mentioned).

#1 - The cheap stereo jack i got from Tayda was a mirror image of the GGG wiring schematic.  So I ended up connecting the input to ring and ground to tip, which grounded the guitar input.  This drove me crazy, because everything looked exactly like the wiring diagram, but since my jack was different it was just plain wrong.  Valuable lesson learned.

#2 - I had a really hard time cramming everything into a 1590B (I don't know how you guys do it).  The input and output jacks ended up being above the PCB, and pushed it down in order for them to fit.  The stereo plug pushed it down enough that it shorted the 9v pad on the enclosure.  I ended up covering those pads with hot glue so they wouldn't touch the enclosure.  Not a very elegant solution, but good enough for the time being.  Any tips on space-management in these dang enclosures (or useful links) would be greatly appreciated.

So that's that.  This is my 3rd pedal, not counting the 5 or 6 I've only breadboarded, and it's been by far the biggest headache.  It can only get better from here.

[Jdansti]

Glad you got it going!  Trouble shooting can be a PITA!

[pinkjimiphoton]

was gonna say, you had a dead short in your power supply...can be wicked frustrating when that happens!!

glad you got it sorted out tho, well done!!

the fuzzface (to me) is the greatest pedal ever devised by mere mortal men...