BYOC Classic Fuzz Not Working

[adamrobertt]

Hey guys. I hope you don't mind me posting this here, but for some reason the BYOC forum will not allow me to login or post any threads - I keep getting an error message across 3 different browsers.

I recently built the BYOC "Classic Fuzz" which is a Fuzzface clone.  Real simple circuit.  I put it together and it doesn't work. When I turn the pedal on, the LED lights up, but I get no sound out of the pedal.

I double checked to make sure all the components were in the right spot (they are) and I reflowed all of my solder connections, but still nothing.  I attached some photos.  I'm either missing something really dumb or maybe I have a bad component?  Any help is much appreciated. Thanks!

[Slowpoke101]

Welcome to the forum.

Check the 47K resistor (top left corner, under bias pot ).
It appears to be 47R or 4R7....But not 47K (yellow, purple, black, red, brown ).


Edit: Hmm...Just found some documentation for the kit. I am wrong  nothing unusual about that  .....It is supposed to be a 47R resistor (which it is ).
I will do a bit more checking but in the meantime could you measure the voltages on the transistors and post them here?

[adamrobertt]

Welcome to the forum.

Check the 47K resistor (top left corner, under bias pot ).
It appears to be 47R or 4R7....But not 47K (yellow, purple, black, red, brown ).


Edit: Hmm...Just found some documentation for the kit. I am wrong  nothing unusual about that  .....It is supposed to be a 47R resistor (which it is ).
I will do a bit more checking but in the meantime could you measure the voltages on the transistors and post them here?

Thanks for your reply.  I'm getting 5.82 volts on the top one and 1.30 volts on the bottom, measured at the collector.

[patrick398]

Definitely got your ins and outs the right way round? And the tips are definitely going to the in/out and sleeves to ground?
Do you have signal in bypass?

[adamrobertt]

Definitely got your ins and outs the right way round? And the tips are definitely going to the in/out and sleeves to ground?
Do you have signal in bypass?

I'm pretty sure yes.  I rechecked them when I was reflowing the joints... but I guess I'll check again.  I do have signal in bypass, yes.

[patrick398]

Always good to start with the 'idiot check'. The amount of times you stress about a pedal not working and then you look and see the guitar cable lying on the floor, mocking you, and the amplifier input staring at you open mouthed.
If you have a multimeter post some voltages. Alternatively spend 5 mins building yourself an audio probe, (an invaluable tool) and follow your signal. We can walk you through that if you're not sure

EDIT: Also, welcome!

[adamrobertt]

Inputs are definitely properly wired.  I did notice that I get 0 voltage at either R1 or R2. Is this normal? I get 9v at the LED.

How do I make an audio probe? Thanks.

[patrick398]

Audio Probe:
https://www.youtube.com/watch?v=IEcyDzYAsuU

Check voltages on the collector, base, and emitter of the transistors. Looks like they're marked C B E on your circuit board. So with black probe on a ground point, (like the battery negative terminal or jack sleeve) and red probe on each of those pins, what do they read?
In fact, before you do that, note the voltage at the power supply positive first, see what juice the pedal is getting.

[adamrobertt]

Getting a solid 9v at the positive terminal.

On the top transistor, I'm getting: C - 5.82   B - 1.30  E - 0.68

On the bottom one I'm getting: C - 1.30  B - 0.59  E - 0.00

No idea what is normal.

[Slowpoke101]

Your voltages are correct (within range ) for a simple NPN silicon Fuzz Face.

I think that doing some audio probing would be then next thing to do.

[adamrobertt]

Your voltages are correct (within range ) for a simple NPN silicon Fuzz Face.

I think that doing some audio probing would be then next thing to do.

Hmm.  I don't think I have the materials to make a probe on hand.  Would doing a continuity test with a multimeter accomplish the same thing?

[stallik]

Do I see a short between pins 6 & 7 on the board? Or is it just the picture

[adamrobertt]

Do I see a short between pins 6 & 7 on the board? Or is it just the picture

Just the photo. I double checked just now

[patrick398]

Your voltages are correct (within range ) for a simple NPN silicon Fuzz Face.

I think that doing some audio probing would be then next thing to do.

Hmm.  I don't think I have the materials to make a probe on hand.  Would doing a continuity test with a multimeter accomplish the same thing?

No, with an audio probe you are essentially giving yourself a portable output, so you start by touching the input, seeing if there is signal, then following the circuit through component by component to see where you lose signal. You do need to have a rough idea of where to expect signal though, obviously the sides of components connected directly to GND or supply or bias won't have signal.
All you need is an old guitar cable, and a capacitor...you can even omit the capacitor but it can be a bit nosier as sometimes you'll have DC on the cable.

You could use a multimeter on continuity mode to go through each connection to make sure you don't have a bad solder or short. Again, you need to be able to follow the schematic. You're looking to continuity between different components, not across individual components.