SOLVED Depot (lack of) Fuzz

[ColorMeBaddFann]

Hello All - Finished up the Depot Fuzz last night. Plugged it in and getting a bypass signal, but when engaging the footswitch I receive a barely there fuzz effect that's very muffled and sort of "blown out" sounding. Definitely does not sound like the EQD Terminal demos I've seen.

Read through all of the troubleshooting threads I could find on this PCB, and I think I've accounted for most of the issues mentioned there... confirmed I have the correct pinout for transistors (tried both PN2222As and 2N2222As for Q1 & Q2... does not appear to be any difference), socketed C3 to try out 4n7 vs 47n, cleaned up the board with isopropyl, offboard wiring looks correct... still same result.

My guess is that I may have mixed up some of the resistor values between the build doc versions (purchased PCB in Feb '22). Does that sound like a possibility based on the symptoms?

Hoping someone could post a photo of the PCB with the silkscreen values. The build doc version currently listed on the Depot Fuzz product page (v1.95 - May '22) component identifiers on the PCB illustration does not match the photo on the product page. And neither have the values like the silkscreen does.

Thanks!

 

[Robert]

 

[ColorMeBaddFann]

Sweet! Thanks! Fingers crossed it's something as simple as me dropping in a wrong value

 

[Robert]

Just went and pulled a PCB from the bin to make sure I was telling you correctly.

You have the most recent revision of the PCB, and the current PDF matches that board. Ignore the preview image on the product page, those aren't updated regularly and are sometimes inaccurate.

When in doubt, follow the silkscreen on your PCB. As far as I can tell all of your component values appear to be correct, although I can't see the pot values.

 

[Fingolfen]

Sometimes I've had issues when socketing transistors on fuzz pedals with their not making good connection. You may try checking the transistor leads to 1) make sure they're shiny, and 2) if you have a means of checking to make sure you have the orientation (E, C, B) correct...

 

[ColorMeBaddFann]

Thank you both! I measured all the resistors added to the PCB and they look to match up with the silkscreen photo provided by Robert. Although I couldn't get a reading on that 1M in the R1 spot... and after much difficulty removed it and found it was correct (d'oh). Will put it back in this evening and double check my cap values as well.

The transistors seem to be making a connection in the sockets... and when jiggling them about no static is present in the signal. But I'll clean them up a bit just to be sure. And will confirm the pot values are correct too.

Is there a desired hfe value for each of them? Or perhaps a voltage I should be receiving? I've got a good number of the PN2222As, 2N2222As & 2N3904s, and have already tried swapping out several times with no discernible change. And used one of those cheapie component testers to ensure I've got the pinouts aligned as stated on the silkscreen.

 

[ColorMeBaddFann]

Not sure what happened, but put the 1M back in the R1 spot, buttoned everything back up and suddenly it's working. I'm guessing it was related to the transistors not making good contact in the sockets as Fingolfen suggested. Trimmed down the leads and bended the ends just slightly so they'd grip a bit better. Ended up sticking with the 4.7n cap in the C3 spot, as 47n sounded a bit too "boomy" to my ears. I guess I can always swap in a larger value later if I change my mind.

To anyone else who's built this one... does the treble pot adjust much sound wise? I'm not able to notice much of a change, but perhaps thats just the way this one is designed.

Anyhow, thanks again!

 

[benny_profane]

To anyone else who's built this one... does the treble pot adjust much sound wise? I'm not able to notice much of a change, but perhaps thats just the way this one is designed.

It’s more of a presence control than a treble cut (like a RAT). It’s a low pass filter with a stock corner frequency at the lowest setting of 2.9kHz. You can increase the TOP pot value and/or C5 to change the range.

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