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13 Answers 13




  • all solder joints. Are they all solid?
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  • Yes, the lead from guitar to amp- common source of problems as they flex and are plugged in and our. – Doktor Mayhem Oct 13 '12 at 10:33
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    The guitar is not picking up mains hum - The player is. When the player is earthed he/she no longer acts as an antennae and the EMI is reduced, as the OP describes. If you want to remove this noise at all times you need to earth your body by alternative means, ie an earthing wrist strap. (Or, you know, touch the strings like guitarists often do...) – Fergus May 31 '15 at 22:15

I see this is an old question, but I think I have another possible answer. I've read a lot of rubbish about fluorescent light noise, but haven't found the answer anywhere. I eventually figured it out myself. I hope this answer will help the next person who comes across the same problem!

It sounds to me like you've got either an earthing problem with your amplifier or an earthing problem with your home electrics. When mains AC passes through a transformer, the 'low voltage' side of the transformer is 'floating', and not connected to earth. This means that the '0Vdc' leg of the rectifier - which is connected to the guitar - will float at mains frequency. This doesn't matter as far as the amplifier circuits are concerned - all the rectifier voltages float together, but it does mean that the metalwork on your guitar will be floating round in potential at a harmonic of the mains frequency. This is where the hum comes from.

It a correctly designed amplifier circuit, this is easily solved: the 0Vdc in the amplifier is connected to earth. This stops the voltage floating, eliminating the hum.

If the amplifier isn't properly earthed, you yourself act as the earth connection - but only when you touch the metalwork on the guitar. That's why you get the hum when you're not in contact with the strings.

I would suggest that you start by checking your amplifier's mains plug: you should really have a three-pin plug with a separate ground pin. If that doesn't solve it, either there's an internal problem with your amplifier, or there is something wrong with the electrics in your house.


It does sound like a grounding issue.




Hope this helps



I know this is an old post, but in case some other rando like me comes along...

As one answerer replied, the pickup selector switch could be an issue. I found this video online that shows how to clean these contacts (I think I'm allowed to post links here):

I wasn't able to do it because the box that houses my pickup selector is fixed shut (no screws) and I can't get inside, but maybe it will help someone else.



Grounding is an issue with a lot of guitars. I build and customize guitars. I've use a lot of these methods. Always check solder joints (if the solder joint is not shinny, then it's probably a cold joint). I check every connection before making the final wiring. I use a small amp (battery power) thus eliminating 60 cycle hum, to check my connections. Once you've decided what's causing the hum (amp or guitar), then you zero in of the fix.

  • Not to disagree, but I've found that new lead-free solder can often give the same look as a cold solder joint but be electrically sound. When my Grandfather passed I had, for a while at least, a reel of very old solder from his toolbox. I was amazed at the consistent, mirror-shine finish on all solder joints. – ABragg Sep 6 '16 at 9:17

99 percent of the time, it's a guitar issue. best bet is to pull out the electronics, (not difficult) and check your ground wires. very common problem with "beginner guitars" cheap wires and no shielding. I use old coax cable or such, with the copper braiding. replace the ground line to your output jack and pow! no more ground noise. 99.99% guaranteed fix

  • Is the implication here that switching a cable to coax fixes the problem? Which part to replace then? I know there is at least one cable from one of the pots to the ground on the jack, that one? I think the ground wire is connected properly, so I figured I'd consider the shielding possibility – Colin D Jul 4 '17 at 18:46

Don's always suspect the guitar first. Always check the preamp area first. A lot of time any good cable when not plugged into guitar but only into the preamp will behave and sound like the guitar in that if you touch the ground on the cable it will get quieter too. That's what you are doing when you touch the metal on the guitar. If then plugging the cable into the guitar doesn't make that noise much worse, then the problem is not the guitar. It's some kind of grounding issues with the preamp, AC wiring, etc.


It is not the guitar It is the guitarist that plays the guitar Our body picks a lot of noise and if it is not grounded (by we hold the strings or any guitar metal piece that is grounded - our body would inject an extra noise into the active pickup Simply - hold the guitar strings to ground yourself or just turn down the guitar Volume pot


I have a roland cube 30 that had the humming problem too. Humming disappear when I touch the strings. I replace the wiring inside the guitars with screened cable the humming did not go away. Then I replace the Amp's power plug. The original plug do not have the earth wire connected. I replace it to a plug with an earth pin and the humming disappear.


Ok! I have read a lot of opinions on this noise issue. I too have a noise problem on my guitars. As my practice amp is battery powered the noise problem has to be solved without reference to the mains. I also have a safety problem with grounding the strings. There is not usually any reason why an amp cannot function with the live, earth and neutral transposed in the plug. Neutral and earth are connected at the supply substation and possibly at your meter. Transposition could leave your safety ground at mains potential, so that with a firm grip on the guitar neck you are nicely primed for a quick interview with your maker the moment you grab a handy metal mike or similar bit of kit. But given that grounding the strings is convention, and that this adds an antenna to pick up noise and inject it into the signal path, is there a way of reducing this? When I build Hi-Fi amplifiers I separate the signal earths and safety earth. This is often called "lifting the ground". I maintain safety by connecting the two grounds with a resistor typically 10 ohm. This resistor is parallelled with two heavy back to back diodes to carry the load under fault conditions. These are sized to enable plenty of time for fuses to blow. My amps are silent, no hum. At some point in the future I will try such a network to isolate the strings from the pickup wiring. The rest of wiring is screened and ought not present a problem on its own. In comparison with amplifiers, the pickups and pot wiring constitutes signal grounding and the strings and associated hardware constitute casing which should be safety grounded or double insulated. The use of a network is an attempt to achieve both in the absence of a true safety earth. There! got that off me chest!

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    Welcome to Music.SE! You raise quite a few good points here, but it's not really evident where you're going with this answer. Could you structure it a bit more clearly? – leftaroundabout Jan 6 '17 at 1:29

Total newbie but I used a power strip to plug my amp into instead of the wall and it seemed to completely solve the problem.


I have a cube 30x same problem buzzes touch the strings and it stops.These amps are double insulated and do not reqiire a mains earth.The mains lead is only a 2 wire live and neutral.The circuitory deals with the fact that it is double insulated and does not require an earth.Mains earth and circuit ground are not the same thing.Putting an earth on a double insulated amplifier could cause problems if the amp is connected to other equipment or in the same ring as an appliance that goes faulty to earth.You could damage the internal components at least.The problem still exists in the cir uit of the double insulated amplifier that gives you the buzz anlthough you have masked it with adding an earth with the possibility of a meltdown of your amp.


Hi all above I correct in some way i fix broadband so I know these things it’s a minefield . some fixes are possible some not :-eg counter coiled extension lead ,turn off dimmer switches, earth yourself Transformers close to each other , check bad earth s ,faulty transformers ie laptop chargers led,lighting using old power supply .old TVs DVD players .. an in balance between earth connections creates different potentials not all can be bonded removing proximity helps so . man and guitar nead to be at same potential.and pedals etc away from amps .and ha ha mains transformers so may have to live with it it’s only a hum .😖

protected by Community Jul 30 '18 at 13:26


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