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I have a small practice amp with a small Klon clone pedal next to my office desk to keep me sane. Both operate by battery or wall plug. When battery powered, it is relatively quiet even with my supposedly “noisy” single coil pickup. But when I plug the amp in I start getting a loud hum. Plug the pedal into the same outlet and the hum is so loud I can barely hear my guitar.
I know this is a common enough problem, but there are so many gadgets and “cures” out there. What have people here found to work for them? I can’t really go to another outlet. The point is the convenience of having a little amp near my desk. What has worked for you, and what hasn’t?
Thanks.
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03-15-2021 04:58 PM
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Hum debugger, but that's another item in the signal chain. At the expensive end there are line power conditioners such as Furman; at the cheap end there's a 3 prong to 2 prong adapter which defeats the ground (the studio I've recorded in uses this approach, which I didn't like; my amp had a built-in ground lift instead).
Power Conditioners & Surge Protectors | Musician's Friend
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Is this what they call “ground loop”? I know that cutting off the ground plug is what some people do, but the fact that it happened when just the amp was in the chain seemed from my research to mean it wasn’t a ground problem. I understood you to need two separate devices plugged into the wall to be a “ground loop”. Obviously, I know near nothing about all this.
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A ground loop is when there is more than one path to ground (for instance when an amp and effects are plugged into different outlets), so it's probably not that, since everything is going into the same outlet.
If the problem is caused by a light dimmer or some other device in the room, a Hum De Bugger will solve that. But if that's what's going on, you'd get noise while running batteries, too. Are you sure you only get noise when plugged into the wall?
If you've ruled that out, that doesn't leave a lot. One possibility is that the instrument cable is picking up hum from the amp or effect's power cable. Try moving them further apart to see if that changes anything. Also try swapping in different instrument cables to see if that makes a difference.
Another possibility is that a wall wart you're using to power the effect or amp is bad, and is leaking EMI detected by the pickup. Try moving the guitar toward and away from the power supply to see if anything changes. Try swapping in different power supplies.
That's all I got.
John
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I don’t think its a ground loop, the only time I ever suffered from ground loop was when when I split the guitar signal from my pedal board to two amps that were both grounded. Taping off the ground on one amp made everything dead quiet again....
This is something else.... maybe you have some seriously “dirty” wall-power there with dimmers, fluorescent tube lights and PC’s plugged to the same outlet?Last edited by Little Jay; 03-16-2021 at 04:34 AM.
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It's possible that the Romex wire to the outlet is poorly connected. One of the screws holding the wire to the plug could be loose. That should be checked, because it's a fire hazard. Turn off the power at the main breaker box, then pull out the plug and check the wires. If you're not comfortable doing this, get an electrician to do it. Most home fires are caused by electrical problems, so check it. It could well be just interference from other devices in the home, but it's best to be certain.
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Dealing with similar nonsense here as well. Tons of RF interference through my studio monitors. Been driving me crazy for months. Randomly discovered the other day that coiling the speaker cables that go from the audio interface to each monitor a certain way and then literally draping each cable a certain way over the front and top of its respective monitor was the cure. Till today. Then I had to coil them another way and deal them a different way. Maddening. My only suggestion is to experiment with different heights of cables in relationship to one another.
Originally Posted by rlrhett
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Each device makes noise when plugged, by itself, into this outlet (that is, the other one isn't plugged in), but neither one makes noise if you plug it into some other outlet? Is that right?
What about other outlets on the same circuit? That is, on the same switch (or fuse) in the breaker box? What other electronic devices are on that circuit?
Do the amp and pedal have two prong plugs or three prong plugs?
If three prong, does using a ground lift adapter (the "three into two" thingie) make a difference? [edit: KirkP correctly points out the safety problem with lifting the ground].
The only test I can think of is to connect a long extension cord to the offending outlet and plug in the amp at the other end -- in a different part of the house. If it's the room and not the outlet, that would change the noise.Last edited by rpjazzguitar; 03-15-2021 at 11:40 PM.
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get yourself a super cheapo ground tester and make sure your outlet is what you think it is!.. grounded!
you can also check voltage with a multimeter...you'd be surprised by the way voltage drifts in many locations...
be safe with it tho!
cheers
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Is it a fairly pure tone at 60 Hz or 120 Hz? (50 or 100 in some countries.)
Or is it more of a nasty buzz?
Don’t disconnect the ground on the power chord. It’s not safe and not necessary.
Kirk
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This is correct. The ground lift adapter eliminates a safety feature. The proper way is an isolation transformer. Originally Posted by KirkP
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Unscientific and grain of salt: In my last house had problems with noise. Got a Furman. Didn't help at all. Sometimes it's the distribution lines and not your local wiring.
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I had no luck with a power strip cleaner-upper, but the HumDebugger worked well.
However, I also had a cheapish Ibanez amp that picked up ambient radio signals and hummed like crazy. It seemed like poor grounding, as it went away when I touched the input jack, but I was unable to solve it, so I sold it.
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I try, Try, to never let signal and power cables run parallel to each other. Separated and crossing perpendicular. Originally Posted by wzpgsr
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Definitely not that. A nasty buzzing. Originally Posted by KirkP
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It’s tougher to diagnose buzzing than 60 or 120 Hz hum but this tip sheet might be helpful. Originally Posted by rlrhett
Eliminating Troublesome Hum & Buzz Created By Electric Guitars - ProSoundWeb
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Do you play in front of a computer?
Does your guitar face the computer.
The other day, my guitar started humming like crazy.
Played around the room and found out... the pickup of my guitar was somehow interacting with my laptop and making it hum.
Odd. But worth a try.
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The reason I don’t think it is the guitar’s pickup is because if the amp is battery powered there is no noise. If the pickup was the source of the buzzing, I would think it would buzz regardless.
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Do you get the buzz when you go straight to the amp without any pedals? You you get the buzz when the pedal is battery powered? If you only get the buzz when the pedal is plugged into wall power, I’d suspect you’re pedal’s power supply is noisy. Poorly designed warts are one of the most notorious sources of EMI, along with light dimmers. Originally Posted by rlrhett
Pedals can also generate internal noise. The Klon has a chip that doubles the voltage from 9 to 18. This chip has an oscillator that I think operates at the upper end of the audible range, then filtered to DC. I doubt that’s your issue, but thought I’d mention it as a possibility.
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If it's clean on battery power and noisy when plugged into AC then it's likely either coming from the outlet, the AC adapter, or the AC circuit in your amp. Originally Posted by rlrhett
- Battery is not interacting with your ground system. If it's the ground at the outlet it could be a lot of things. You could try ground lift first. But there are other possibilities. Extra noisy ground loops. Crosstalk in your AC with a noisy device plugged in somewhere in the house (older appliances, something with a motor, or fluorescent lighting). Noisy input from the power plant.
- Are other amps plugged into that outlet noisy?
- Is the amp noisy plugged into different outlets? (try closer and farther from the circuit breaker box)
- Does the AC cord have a transformer on it or is it just an AC cord? If it has a box on it, can you make sure that isn't getting too close to a noise source. Any way to try a different cord?
- If it's the AC circuit inside the amp don't know what you do about that. With repair costs being what they are, probably a new amp.
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