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For my "teach myself for to solder" project I picked up a BYOC Tremolo. I recently finished putting it together and I'm having an issue with the pedal making a loud pop when I turn it on. It also pops when I turn it off, but not as loudly. I did a test where I plugged it into my audio interface's guitar input, set my gain so the guitar was hitting around 60-70% of the meters, and when I turned the pedal on the pop would briefly clip the input. The levels were fine after that pop - until I turn it off and there is another pop, but at least this one doesn't clip the input.

Other than the popping, the pedal seems to work fine. It powers on and it tremolos - but I do find it starts to distort if I have my Epiphone Les Paul's volume above half way, but I'm less concerned about that for now.

This is my first project that's more than reconnecting a wire to an XLR jack, and I believe most problems are user error. So I'm guessing I made a mistake somewhere along the way. I thought the footswitch was the hardest thing to wire so I'm not surprised it's the thing giving me trouble after the build.

In terms of troubleshooting, I read that LED pop could be the issue, so I lifted one of the LED legs but that didn't fix it. I've double checked that my footswitch wiring matches the instructions, but haven't rewired the switch yet. I've read a bit about pull down resistors, but since this is my first project I don't have any spare parts to experiment with. At this point I've stared at this PCB so much that I'm sure I'm overlooking something. Attached are photos of the build with hopes that someone more experienced than me can spot what's wrong.

PXL_20211026_175743036 by trendyrico, on Flickr
PXL_20211026_175800576 by trendyrico, on Flickr
PXL_20211026_175823365 by trendyrico, on Flickr
PXL_20211026_175855201 by trendyrico, on Flickr
PXL_20211026_175916496 by trendyrico, on Flickr

This circuit already has a pull down resistor, so don't be drug down that rabbit hole.

Switch pop is typically caused by one of two things. A static charge build up on the switch contacts or DC voltage leaking onto the circuit input or output (almost always the input).

A static charge will typically be weather dependent and do away after actuating the switch on and off several times.

DC leakage does not go away with switch actuation and is typically measurable with a multimeter by measuring DC voltage at footswitch lug 5 to ground in bypass mode (usually less than 1 volt).

Also, here is solid advice for all beginner kit builders: http://www.byocelectronics.com/board/viewtopic.php?f=9&t=52188

http://www.byocelectronics.com/board/viewtopic.php?f=9&t=52211

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MasterDelayer/Reverbrador/Ampaholic/TopJacker

Thanks for the advice!

I don't think it's static as it does not go away after I turn the pedal on/off several times. I don't currently have a multimeter, so I need to pick one up before I can troubleshoot any further.

If you have a Harbor Freight store nearby, you can pick up a perfectly serviceable multimeter there for $7: https://www.harborfreight.com/7-functio ... 63759.html

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Good to know!

After picking up the multimeter from Harbor Freight that was kindly suggested above, here's what I've found:

- I'm testing while using battery power. Measuring the positive of the battery shows me 8.35 volts, which makes sense as this is not a brand new battery.
- The LED reads 8.2 when bypassed, and varies when the pedal is on (which I'm guessing is from the fact that it pulses with the rate.)
- When using the 2000m setting on the multimeter and the pedal bypassed, lug 5 reads -000, with the occasional jump to 001. With the pedal on I've only seen 000.
- The only lug that shows any voltage is lug 1. It reads around 6.1 volts when the pedal is bypassed. That drops to 0 when the pedal is on, and then climbs back up to 6.1 when bypassed. Since no other lug has voltage I'm currently confused as to where this is coming from Is it normal to have that build up on the lug that feeds the effect input?

Couple of comments:

1. When measuring pedal voltages, you generally want to use the 20VDC setting on your multimeter to get the best measurement precision possible.
2. I would closely inspect the solder joints for capacitors C1 and C4 (see PCB map below), since these are the coupling caps (i.e. DC voltage blockers) at either end of the effect circuit. Make sure that there are clean joints for both legs of those caps, with no wire strands, carbonized solder mask or other contamination around them. This is particularly important for electrolytic caps like C4, where the two solder joints are immediately adjacent to each other.
3. If this doesn't improve the situation, I'd strongly consider replacing those two caps, starting with C4.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks so much for the advice. I didn't see anything that looked like it could be causing problems, but I went ahead and reflowed C4 and C1. The popping is slightly less loud now, but still much louder than it should be. I think I'm going to go ahead and order some replacement caps for those two to see if replacing them will take care of the issue.

My replacement caps came in over the weekend, and I've gone ahead and swapped them out. I replaced C4 then did a test, and since it was still popping I moved forward with replacing C1, and the pop is still there.

Out of curiousity I measured what C1 and C4 have flowing through them. C1 was 3.23 and C4 was 5.55, and neither changed between the pedal being bypassed or active. I couldn't see any jumps when I turned the pedal on or off either.

I also ordered a replacement footswitch, just in case there's something mechanical going on with the one that came with the kit. I haven't swapped that out yet, but we'll see how it goes after I do that.