parentheses mini fuzz - no sound or LED lightup

SurelyTheEnd

New member
Hey there,

I've built before but not with Pedalpcb. I picked up this kit to build, excited to try it out but after wiring up, there is no sound or functioning LEDs when the pedal's engaged. It passes sound, so that's at least something. The guts look like as below, it's late so I can add other pictures tomorrow. Any initial thoughts? Thanks in advance!

EDIT: So I tried it this morning, but this time with the knobs up from zero because clearly my brain ceases to function after midnight :mad: the boost section seems to be working but the rat/octave is only generating white noise. I can turn up the gain/volume/filter and the noise changed accordingly but I get no guitar sound. Any suggestions?

 
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What kind of meter are you using?

Q1 source voltage is too low. Either Q1 is out of spec, R4 is the wrong value or there is a short on the board.

Q2 looks ok. Your meter is loading down the base voltage reading. What is the part number of D2 & D3? If they are Russian, then they are facing the right way in the pic.

Q3 is saturated or shorted. Might be a problem with Q4, might be something else.

Q4 readings are all way off. I suspect you were really measuring Q5. Take readings from Q4 and report back.

Q5 (assuming the transistor you called Q4 is actually Q5) readings are off, just like Q1. My guess is Q1 and Q5 are both out of spec.

Q6 is the boost, you're calling it Q5. Readings look ok.

IC1 readings look ok except pin 3. Your meter is loading down the circuit when you measure pin 3. Verify R6 is 1M.

Do you have any other JFETs to sub for Q1 & Q5?

Recheck all of the resistor values visually.
 
The fact that you pass clean signal, and hear the white noise change "appropriately" when manipulating pots, coupled with the fact that you do NOT have working LED, hints to me that the problem is somewhere in the power.... something is not getting to the bias section of one or more of your transistors. trace the 9V path from input to each "feed" to the major components. If the power LED doesn't light up, there isn't a good path for current. I made the mistake once of using a 2.2M resistor instead of a 2.2K for the LED resistor. Had similar symptoms.
 
Another Member was having issues with his Build.
If yours is a Musikding kit, you probably have Fake PF5102's or Duds!
Try 2N5458 or another JFET in Q1 & Q5 and your pedal may work
 
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