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Hey Folks,

Having a strange issue with a recently completed build of the Li'l Breaker kit. Here are some of the things I've done/discovered:
- Pedal operates correctly - Tone/Vol/Drive and overall effect seem to function and sound correct
- With tone and Vol at 12 o'clock, turning the drive pot up anything past halfway increases a noisy buzz
- Buzz goes away when in bypass
- Buzz is significantly worse when not touching metal on guitar or amp (same buzzing effect is also experienced with guitar directly into amp, but with 10x less buzz)
- Pedal is acting like a contact microphone... Tapping on it perfectly picks up the vibrations and amplifies it. In fact, with nothing on the input at all, just the Li'l Breaker directly into the amp (tried 2 diff amps) I can flick the input wire (with the pedal open) or tap the case and it will amplify like a mic.
- When in bypass with amp turned up I've verified it still acts like a contact mic, just with less amplification from the circuitry.
- I've focused my troubleshooting on the 3PDT switch, and input/output jacks wiring. Nothing strange popping up. I'm guessing there's some type of ground loop or some other grounding issue here, but kinda stumped. It's a very simple circuit though I don't think it's circuit related... Something else at play?

Any ideas? I can get some photos uploaded at some point.

Thanks!
Zesty

Let's see those photos, please. Make them large, well-focused, well-lit shots of BOTH sides of the PCB and all of your jack and switch wiring.

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

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

OK, so I took the time this weekend to recheck everything. Re-flowed all solder joints, shortened up all wiring to the absolute minimum. I removed the jacks and took a deburring tool to grind off the paint on the inside of the holes to ensure good ground conductivity between jacks. Took some pics I'll try to link here.

My findings:
- Pedal sounds exactly the same
- Again, functions correctly, and when bustin' out some Angus Young chords it sounds very good. But as soon as I stop, and especially when not touching the guitar, it is buzzing very loudly with the Drive knob up past noon. Effect doesn't really do much without the drive cranked past noon anyhow.
- I've tested it with the bottom cover off ensuring no components are shorting out on anything. No change.
- I've tested with different guitar cords and amps
- I've taken a single enclosed jack in-air, plugged it into the input of the amp with a cord (nothing else), and it buzzes like crazy (as expected), and if I flick the tip input it does act like a contact mic, so that's just normal I guess when it's not getting a good enclosed ground or whatever
- I've plugged into just my Large Beaver, active or bypass, and it's silent.
- I've tried the Li'l breaker in series with my pedal board, and all by itself. Its the only pedal exhibiting noise like this. My Large Beaver when active is almost silent compared to this pedal.
- All buzzing goes away from the Li'l Breaker when I switch on certain other pedals in the chain at the same time (like my Neutron for example). Maybe it's decoupling a ground loop or some other noise path?

One thing I haven't tried is a new TL072 chip (don't have one on hand). The one I received was badly mangled in shipping. I managed to straighten all the pins, and since the pedal seems to operate correctly (other than the buzz) I'm doubtful anything is wrong with it.

What I suspect is this:
- Pedal is built correctly, and functioning (somewhat) correctly
- This type of dirt pedal circuitry or design/layout is, for some reason, amplifying noise already existing in my setup?
- Or... I've got a bad Opamp? Or a noisy Opamp? Or?

I'm out of ideas. I've got a Li'l Modified OD kit here that I haven't started building, but I'm curious if when I complete that build if it exhibits any similar buzzing. I hope not! I've got at least a dozen effects on my pedal board (lots of BYOC kits) at the moment, and not one amplifies noise like this, so hopefully this is something I can fix!

I'll try some PhotoBucket links here. Underside PCB photos were taken when I had removed it from the box and disconnected all of the pot/jack wiring.















Thanks for any help/ideas!
Zesty

Coupl'a things:

* Have you tried it as the only effect in your chain? That is, guitar->Breaker->Amp? Does it still buzz?
* What guitar are you using? Are the pickups single coil?
* Can you hear the buzz (even if much quieter) with the pedal off?

In my experience, buzzing such as you describe generally comes from one of three sources:

1) A poor ground connection: Re-flow the ground wire connections on the I/O jacks and the PCB will generally remedy this.
2) Power supply noise: Some P/S's don't get along with some pedals, so try another P/S and see if the buzz is still there. Normally, I'd say try a 9V battery, but unless you have a battery to DC jack adapter, this isn't readily doable with the BYOC mini pedals.
3) A bad op amp: If the previous two don't get you anywhere, try replacing the TL072 op amp. Contact sales@buildyourownclone.com, ask for a new TL072 and tell 'em that a forum moderator sent you. They'll send you one at no cost. If you don't want to wait a few days for that approach, you can probably find one at any good electronics supply store. Doesn't have to be a TL072--any general purpose dual op amp should work fine. I wouldn't attempt to try to de-solder the existing op amp in one piece; de-soldering an 8-pin component from a PCB is a huge PITA. Cut the legs with a small pair of cutting dikes and then de-solder the legs individually. Clean the solder out of the PCB eyelets with a solder sucker or good quality de-soldering braid, and then install the new op amp.

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

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

Hey Guys,

Thanks for the suggestions... much appreciated! I apologize for the late reply. I do not get as much time these days to indulge in my projects and gear.

In response to mmarsh:
1) Yes, I tried the Li'l Breaker as the only effect in the chain. Still buzzing when drive set to full.
2) I have tried diff guitars (single coil and humbucker), but the buzzing is there even without a guitar on the input.
3) No buzzing with the pedal off (other than the general "normal" noise in my setup)

In response to duhvoodooman:
1) Yeah, I figured a poor GND would be to blame as well, but I/O jacks were reflowed with no success.
2) Great suggestion on the battery (should've thought of that myself)... yes, I have an adapter like that. Unfortunately, still buzzing when the drive is cranked.
3) So, yeah... out of options and was suspicious about the op amp too. Seeing as the pins were mangled in shipping I thought I'd replace the chip to see what happens. I have a good solder sucker and manged to get it out mostly intact (had to cut two pins). I had no other TL072 chips, but I found an old LM833 in my tackle-box from my college days (mid 90's). Is that considered vintage now?! From what I've read online, it's an excellent substitute for the TL072 with possibly lower noise.

So verdict is... no real change in buzzing amount. Arrrrrgh!!! A little disappointing, but the pedal is still usable. The LM833 is definitely not buzzing quite as loud, but as soon as the drive knob is cranked up anywhere past about 1 o'clock, the buzz is intense. Gets much, much more intense if I stop touching the guitar. (Read LOTS of threads about guitar/amp/pedal grounding, and there are some crazy ideas out there). Seeing as about a dozen of my other pedals of mixed origin do not suffer from any kind of buzzing, I'm convinced it's something with the Li'l Breaker. Starting to think it's just a noisy pedal by design.

I'm working on my Li'l Modified OD now. I'll report back if it suffers from any buzzing.

Any more suggestions for me, fire away!

Thanks for the help!
Zesty

I can assure you from personal experience with my own Li'l Breaker that this is most definitely NOT normal behavior and isn't a design issue. ine is no more nosiy than any of my other low to medium gain overdrives. And if it were merely amplifying noise already in your signal chain, then I would expect something like the Large Beaver with its four cascading transistor gain stages to be MUCH worse in this regard. So I believe the problem is definitely due to an anomaly in your pedal, but it's not at all clear what that is. I don't see anything out of place, and you've already worked through many of the actions we typically recommend to solve these types of issues.

I do seem to recall a noise problem posting from a few months back that turned out to be a bad electrolytic capacitor. Do you happen to have (or could readily obtain) a couple of spare 47uf electros to replace the ones that came in the kit? If you have 100uf's, those would be just as good. These small electros only cost a few cents apiece, so it would be a cheap fix to try.

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

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

You are giving me hope again!

I'm very encouraged to hear you have a Li'l Breaker and it is not noisy... gives me hope that I can figure this out. And yes, my Large Beaver is silent, so good to hear it's nothing in my chain (which I had kinda already determined anyhow).

OK, I'll dig around my tacklebox for some electrolytic caps. I can definitely find some within that range to at least try and see if it solves it.

I'll report back with my findings.

Thanks again for the help!
Zesty