Fuzz Face Clone not Making any Distortion/Fuzz

[samsquanch]

Hey y'all!

Working on my first clone that isn't from a kit. I'm loosely following this schematic with mostly the same parts (swapped the germanium transistors with silicon, trim pot switched with a 20k ohm pot, and 10nF cap with .01uf cap):

https://www.synthrotek.com/kit-assembly-instructions/effect-pedals-assembly-instructions/fuzz-face-clone-assembly-instructions/fuzz-face-clone-bom/

When the pedal is on, the LED cuts on, and you can hear the knobs making a tad bit of an adjustment, but there is no fuzz whatsoever. It actually sounds like it is compressing the signal (sounds like it fully bypasses the pedal when off). Attached are pictures of what I'm working with. Note the last one I jumped two of the pins on the trim pot. I read you need to do that if you use a regular pot. I removed the jump and it makes the pedal dead silent when turned on.

Let me know if y'all have any ideas and if I can provide and more details. My first stab at a semi-winged modification to the clone, so I'm sure I made a few dumb mistakes along the way. Thanks!

[antonis]

Your PCB Trimpot tracks make no sense to me..
(or my coffee isn't strong enough..)

1. Remove jumper and lift B20k pot wiper wire (lug2)..
2. Connect wiper wire to C2 negative leg..
3. Wire B20k pot lug1 to any convenient PCB GND..
(it should be a good idea to run a twisted pair of wires 2&3 to C2 negative & positive leg respectively..)

P.S.
Verify good connection between C2 positive leg & GND..

[samsquanch]

Your PCB Trimpot tracks make no sense to me..
(or my coffee isn't strong enough..)

1. Remove jumper and lift B20k pot wiper wire (lug2)..
2. Connect wiper wire to C2 negative leg..
3. Wire B20k pot lug1 to any convenient PCB GND..
(it should be a good idea to run a twisted pair of wires 2&3 to C2 negative & positive leg respectively..)

P.S.
Verify good connection between C2 positive leg & GND..

Thanks for you reply! I'll try this out tonight when I get home from work!

[samsquanch]

Still no luck. I triple checked everything and it fits the schematic despite a small difference in a couple of the parts. It sounds like the pedal is working fine (light cuts on, all knobs change the sound), but there is just no fuzz whatsoever. Could the transistors be bad? I'm swapping those for a fresh pair tonight hoping that's the issue.

Anyways, at wits end with this one. Gonna gut it and try again with the exact parts in the listed when I can find them...

[willienillie]

swapped the germanium transistors with silicon

Did you also swap from PNP to NPN?  Because that would require reversing the polarity of the power and the electrolytic caps.

...and 10nF cap with .01uf cap

Same thing.

[samsquanch]

swapped the germanium transistors with silicon

Did you also swap from PNP to NPN?  Because that would require reversing the polarity of the power and the electrolytic caps.

...and 10nF cap with .01uf cap

Same thing.

Ok, I think you are onto something. I do believe the build required PNP, but I ordered NPN. Can simply flip the caps? I'll need to check on how to reverse the polarity of the DC power.

[antonis]

I do believe the build required PNP, but I ordered NPN.

How did this happen..?? 
Kit assemply clearly states choise between AC128 & 2N3905 (which actually is a 2N3906 of about half current gain..)

[samsquanch]

I do believe the build required PNP, but I ordered NPN.

How did this happen..?? 
Kit assemply clearly states choise between AC128 & 2N3905 (which actually is a 2N3906 of about half current gain..)

Rookie mistake...

[samsquanch]

So I wasn't able to find 2N3905, but found 2N3906 to swap out the NPN transistors with and added a trim pot instead of the third pot. Still, LED cuts on, knobs change the sounds, and a clean signal comes through, but no fuzz whatsoever.

[Kipper4]

Isn't 2n3906 PNP?

[samsquanch]

Isn't 2n3906 PNP?

Yes it is. By mistake, I initially added NPN when the spec called for PNP.

[willienillie]

I'm guessing based on the assembly instructions that your transistors are installed backwards.  They show silicon transistor installation for CBE pinout transistors, but your 2N3906s have the more common EBC pinout.