Volume Pedal Noise - Troubleshooting

Mathew Peluso · Post by **Mathew Peluso** » 20 Nov 2024 12:54 pm

Hey all, I’m hoping someone can help with an issue that I can’t seem to figure out. I have a newer Goodrich L-120. Shortly after getting it I noticed a noise in the sweep. I assumed this was a bad pot and Kevin at Goodrich was super helpful and accommodating by swapping out the pot. He mentioned that he wasn’t picking up the noise when testing and suggested that it’s likely something else in my chain but replaced the pot anyhow for peace of mind. I found that the noise was gone initially but started to come back after a few months. The noise is in the exact same spot of the sweep so two bad pots would be extremely unlikely. I then did a lot of troubleshooting:

Steel to volume pedal to multiple amps
Multiple six string guitars to volume pedal to multiple amps
(Different cables at both points in both scenarios)

VP to multiple amps with no input/guitar (Different cables)

Played with the volume pedal on multiple amps in different buildings to rule out electrical in my house.

In all of these scenarios the noise was present at the same volume and in the same part of the sweep. I’ve confirmed with a multimeter that there isn’t any DC leakage from the input of my Milkman Half & Half. Since this is occurring on multiple amps something has either damaged the pot or there’s another factor. The trouble is I have no idea what else could be happening here. Is it possible my pickup is the source? I’m no expert in electronics but I don’t see how that could be the case. For reference, it’s a Telonics X10 in a Williams 700 series S10. Thanks in advance for any help with this!

Dennis Detweiler · Post by **Dennis Detweiler** » 20 Nov 2024 4:11 pm

Maybe try spraying some contact cleaner (Detoxit) into the pot. If that temporarily solves it, it has to be the pot again. I installed a new pot into my ShoBud pedal a few years ago and it had a very short bad spot in the sweep. I bought another one and it was good.
Also, if you have a multimeter, use it as a continuity test and see if it reacts.

Danny Letz · Post by **Danny Letz** » 21 Nov 2024 7:11 am

Don't know what the symptoms would be & it's unlikely this would be one, but make sure the retaining nuts are tight on all the jacks.

Scott Swartz · Post by **Scott Swartz** » 21 Nov 2024 10:24 am

Possibly a static electricity issue in the VP or maybe even somewhere else like touching knee levers or metal at that point in the sweep, you can check continuity with a meter and try grounding things with alligator clip leads.

viewtopic.php?t=403371

Mathew Peluso · Post by **Mathew Peluso** » 21 Nov 2024 1:17 pm

Thanks for the suggestions!

- From what I can tell the pot is enclosed so I’m not able to spray any contact cleaner into the pot.

- I can confirm that the jacks are all secure.

- Scott, this is interesting and I’d be surprised if this was the case. I’ll do some further troubleshooting with this in mind. Could static electricity damage the pot or would it just be an audible symptom while the static electricity is present? The reason I ask is that I get the same noise when using the pedal with no guitar plugged in (just cable from output of pedal to amp). So maybe that means that static electricity could be a factor in the volume pedal itself.

I suppose it’s possible that I just had a couple of bad pots. I’ve ordered a couple Dunlop pots from Tom Bradshaw just in case. I’m determined to get to the bottom of it before replacing the pot though, just figure I might as well have some on hand anyhow.

Tucker Jackson · Post by **Tucker Jackson** » 21 Nov 2024 1:23 pm

Good info, Scott.

How would one go about checking for a static problem in the pedal? Something that should be grounded... isn't, right?

Scott Swartz · Post by **Scott Swartz** » 21 Nov 2024 3:12 pm

Yes, if a metal part is not grounded (like the knee lever and pedal bar discussed in the thread) it can build up static electricity and create a intermittent static-y sound in the audio.

So you would check and find any ungrounded parts, and then ground them with a clip lead and see if it goes away. If thats the fix them add a permanent ground wire.

Tucker Jackson · Post by **Tucker Jackson** » 21 Nov 2024 8:00 pm

Thanks Scott... I should have been more clear. How would one check for static inside a volume pedal? Crack it open and do the alligator clip thing on the ground of each of the three jacks, maybe?

Dennis Detweiler · Post by **Dennis Detweiler** » 21 Nov 2024 8:15 pm

If you used the volume pedal into six string guitars and into different amps, I think that would rule out the steel and amp and has to be the volume pedal causing it? I bought a new Dunlop replacement pot for my ShoBud pedal a few years ago. The new one had one place in the sweep that dropped out. I ordered another one and same problem. I finally went to a Dunlop 2027 pot with the orange casing and no problems. It's 500k. Advertised as the lifetime Super Pot.

Scott Swartz · Post by **Scott Swartz** » 22 Nov 2024 9:18 am

Tucker, the jacks and the lower body should be well grounded, I was thinking it could possibly be the treadle, but any static electricity issue is very tricky. I would not have believed a knee lever could introduce noise into the signal until I was having this issue and discovered this fix. Another steel I was having the issue on was fixed by grounding a cross shaft support.

Also the noise I am referring is a short intermittent sound, similar to the wearing a sweater in the winter static shock phenomenon.

Its a build up and discharge type thing so the static has to build up again before you will hear another short sound of the discharge.

Marshall Woodall · Post by **Marshall Woodall** » 22 Nov 2024 9:28 am

I don't have much to offer in terms of a solution but I found I was having a problem with a passive volume pedal (running right off of the pickup) when attached to my Peterson Stroboplus tuner (from a dedicated tuner out) if the tuner was plugged into a DC adapter. Obviously this would imply a dc leak but I have never been able to measure anything. Funny thing is that a buffer in line with the pickup before the pedal eliminated the issue. Go figure-

Bob Sykes · Post by **Bob Sykes** » 22 Nov 2024 4:54 pm

This is a long shot sort of related to what Scott is describing. It's theoretically possible to build up some static charge on the string. Depends on what the string and pot shaft surfaces are made of. Maybe friction in the pivot too.

One way to eliminate this is with a topical antistat. I'd avoid a spray type but might be able to rub a fabric softener sheet on those parts..

Mathew Peluso wrote: [...] Could static electricity damage the pot or would it just be an audible symptom while the static electricity is present?

A typical static discharge (ESD) event would not damage the pot. Lightning (also ESD) OTOH would fry it.

ESD in audio systems will sound like a snap or pop (no crackle)

If you have a portable AM radio, tune it in between stations and you will be able to hear ESD events nearby.

Gary Meixner · Post by **Gary Meixner** » 23 Nov 2024 6:10 am

Mathew,

Can you describe the sound in more detail? Does it occur as you are actively turning the pot, or appear when you reach a certain point in the rotation and remain (at least temporarily) when you stop rotating?

Static would most likely require movement, and once discharged require more movement to build up again. If the noise was from an external AC source it would hold, at least temporarily, when you stopped moving.

Could it be the body of the pedal is creating a capacitance, acting like a tuner and attenuating an AC signal from some outside source, becoming audible when the two halves of the pedal body come closer together.

You may have experienced something similar tuning an old AM radio; when reaching for the tuner knob a capacitance would build up between your hand and the radio and create audible interference.

No expert - just trying to help.

Gary

Mathew Peluso · Post by **Mathew Peluso** » 23 Nov 2024 1:54 pm

Thanks for all of the helpful info here! Based on what I’m reading, I don’t think this is due to static electricity.

The best way I can describe it is a scratchy sound that occurs consistently from about a third of the way from the off point to a little over the halfway point of the sweep (typically what I imagine when people talk about a pot going bad). The noise is not present if I park the pedal within that range, only when actually moving through the travel of the pot. The audio from my steel does not drop out at all and in the context of playing with a band it isn’t an issue. I can definitely hear it in isolation and it is audible when recording. But again, not really detectable with other instruments in the mix. I think I’m just going to change the pot when it arrives and I’ll update here if that does the trick. I’m not really sure what else to do and it’s a relatively inexpensive test.

Bill Fisher · Post by **Bill Fisher** » 23 Nov 2024 11:49 pm

Just get a new, good quality Potentiometer, and put it in there. That's probably all there is to this. That's what your description sound like to me..

Bill

Stephen Cowell · Post by **Stephen Cowell** » 24 Nov 2024 3:18 am

If a DC offset voltage is on the circuit it would cause the pot to be noisy when moved... what kind of buffer or other pedal is used? A big series capacitor would stop this noise if this is the problem.

Dave Grafe · Post by **Dave Grafe** » 24 Nov 2024 3:49 am

Stephen Cowell wrote:If a DC offset voltage is on the circuit it would cause the pot to be noisy when moved... what kind of buffer or other pedal is used? A big series capacitor would stop this noise if this is the problem.

My thoughts also.

Mathew Peluso · Post by **Mathew Peluso** » 24 Nov 2024 6:22 pm

Bill, replacement pots are on the way but I was hoping to find another explanation since this has now happened twice in the exact same spot of the sweep. Could definitely be a coincidence though!

Stephen, I’m using a Sarno Freeloader between pickup and Goodrich at all times. I have a small pedalboard as well (post volume pedal) but this noise is still present when troubleshooting with/without anything else in the chain, including the steel. Can you elaborate on what you mean by a big series capacitor?

Dennis Detweiler · Post by **Dennis Detweiler** » 24 Nov 2024 9:21 pm

I am confident that it's the coincidence of the two bad pots.

Dave Grafe · Post by **Dave Grafe** » 25 Nov 2024 2:23 am

If it was fine when Kevin tested is it just possible the VP is plugged in backwards? There are a number of ways that a perfectly good pot could produce the noise you mention and that one's the easiest to fix.

Gary Wessels · Post by **Gary Wessels** » 29 Nov 2024 10:14 pm

Matthew,
I've encountered an identical situation with my L-120.
I'm on my 3rd pot now (from Bradshaw this time) and hoping that solves it...
Gary

Stephen Cowell · Post by **Stephen Cowell** » 30 Nov 2024 7:12 am

Mathew Peluso wrote: Stephen, I’m using a Sarno Freeloader between pickup and Goodrich at all times. I have a small pedalboard as well (post volume pedal) but this noise is still present when troubleshooting with/without anything else in the chain, including the steel. Can you elaborate on what you mean by a big series capacitor?

Like a 1uF ceramic in series... 'big' is relative here... much bigger than a tone bleed cap I'm saying... we want to pass all AC and block all DC. If you've got a voltmeter (every one of us should!) you can measure the tip to ground voltage coming out of your amp or effect and look for DC. Good luck!

Lee Baucum · Post by **Lee Baucum** » 30 Nov 2024 7:51 am

I know close to nothing about electronics; but, this is an interesting discussion. Can't wait to see how the problem is solved.

I installed pots purchased from Tom Bradshaw in both of my old Goodrich volume pedals.

They have been working great for a little over 15 years.

Mathew Peluso · Post by **Mathew Peluso** » 30 Nov 2024 4:50 pm

Thanks again for all of the helpful replies here! I gave up on trying to figure out if anything outside of the pot was contributing, though I did test for DC leakage from the amp, post effects and post Freeloader with nothing showing on my multimeter. Pot has been changed and all is well. I’ll report back if I run into this again but I’m hoping it was just a couple of bad pots and I won’t have to think about my volume pedal for some time.

Bill Cash · Post by **Bill Cash** » 3 Dec 2024 10:23 am

I have 3 Goodrich passive pot volume pedals. 2 from Oceanside and 1 from when they were produced out of before. Georgia? (I forget offhand where exactly they were made originally) I’ve experienced this exact problem with all 3 of them at some point, it drove me crazy I would pry open the pots to deoxit them for only temporary avail. A few months later the scratch would reveal itself again. I was confused as to why enclosed pots would get dirty so fast, so I’d swap out new ones to only have the same reoccurring problem. It only took me swapping things once or twice to see that the problem was the wire that comes stock in the volume pedals frays very easily. I rewired the pedal with the original pot and new wire and it so far has gone years now without making itself known again. I’ve gotten 2 more since that initial problem and I’ve had that same problem happen with both of them and when it has happened I just go straight to rewire them and haven’t had it happen since. I’ve used 22awg solid core wire, but I don’t imagine it matters too much what is used. I don’t want this to be taken as Goodrich slander either I love their products and prefer their pots over the other 470k’s I’ve tried and until now I’ve only heard about this happening to me I figured I had an unlucky right foot or something, but hope this helps anyone else experiencing this problem.