Bare Knuckle Pickups Forum

Forum Ringside => Tech => Topic started by: Hammerheart on January 19, 2013, 08:57:18 PM

Title: Mains hum that disappears with hand contact on all my equipment.
Post by: Hammerheart on January 19, 2013, 08:57:18 PM
On all amps, all guitars (apart from the one with an emg in it) in all sockets around the house i get a hum which disappears when i touch the metalwork of the guitar. Ive checked the sockets with my socket tester and it appears they are wired corretly and not missing the earth. Any ideas on what the problem might be? I've only lived here just over a month and it never used to do it in my old home. I'm an electrician by trade but I'm stumped by this. I'm going to check inside the fuseboard in a second to see what I can see.

The most annoying thing about this is the slight popping sound when i come into contact with the guitars. It's getting to be annoying now.
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: Twinfan on January 20, 2013, 12:37:39 AM
If you're a sparkie, and you don't know, how are you expecting us to?????!!!  :?  :lol:
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: JJretroTONEGOD on January 20, 2013, 01:37:41 AM
On all amps, all guitars (apart from the one with an emg in it) in all sockets around the house i get a hum which disappears when i touch the metalwork of the guitar. Ive checked the sockets with my socket tester and it appears they are wired correctly and not missing the earth. Any ideas on what the problem might be? I've only lived here just over a month and it never used to do it in my old home. I'm an electrician by trade but I'm stumped by this. I'm going to check inside the fuse-board in a second to see what I can see.

The most annoying thing about this is the slight popping sound when I come into contact with the guitars. It's getting to be annoying now.

is the inside of your electric guitar shielded? it needs to be grounded properly! take it to a guitar tech
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: sjwebb90 on January 20, 2013, 04:57:12 PM

Does your new abode have dimmer switched lighting?

This are notorious for creating nasty buzzing on guitars and amps when the lights are switched on.

Just a thought, as I have the same issue at my gaff when the dimmer is switched on downstairs! Turn the dimmer off and the noise goes away!

Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: Hammerheart on January 20, 2013, 11:55:39 PM
If you're a sparkie, and you don't know, how are you expecting us to?????!!!  :?  :lol:

Lol yeah I know. Trouble is I can't find a single thing wrong with the electrical installation but its affecting all my guitar amps. There's only one dimmer and I've made sure its off.
The fact it goes away when I earth the guitar with my body means something isn't earthed but everything tests out ok. It's happening with all my guitars and all 4 amps

As a sparky this isn't the kind of thing I'm usually asked to find out. I certainly don't deal with electronics in any way.

I'll have to unplug everything in the house tomorrow. Hopefully I can isolate the problem.
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: Twinfan on January 21, 2013, 08:19:03 AM
Have you tried plugging into different sockets around the house to see if that helps?
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: darkbluemurder on January 21, 2013, 10:56:40 AM
On all amps, all guitars (apart from the one with an emg in it) in all sockets around the house i get a hum which disappears when i touch the metalwork of the guitar.

Assuming the electric sockets are wired correctly and the amp's safety grounds are intact, a bit of hum reduction when touchng the metal parts is normal. The reason is that once you touch a metal part your body gets grounded and acts like a shield. The effect can be minimised by shielding the wiring in the guitar as much as possible. Putting covers on humbuckers also helps in that regard. However, it will not be possible to eliminate all of it since the pickups are susceptible to picking up stray noises as well, and if you shield them completely in a case you shut them off from the strings rendering them unfunctional.

The standard EMG set up does not ground the strings so you will not have the additional shielding effect by touching the strings since your body will not be connected to ground.

If you get crackling or loud popping you could have problems with static charge. This happens with guitars with plastic pickguards sometimes. Putting some aluminum foil underneath the pickguard helps and also adds shielding.

Cheers Stephan
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: Hammerheart on January 21, 2013, 11:57:07 AM
Have you tried plugging into different sockets around the house to see if that helps?

yeah. Its on all sockets and all circuits.

Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: Hammerheart on January 21, 2013, 12:05:24 PM
Assuming the electric sockets are wired correctly and the amp's safety grounds are intact, a bit of hum reduction when touchng the metal parts is normal. The reason is that once you touch a metal part your body gets grounded and acts like a shield.

If you get crackling or loud popping you could have problems with static charge. This happens with guitars with plastic pickguards sometimes. Putting some aluminum foil underneath the pickguard helps and also adds shielding.

Cheers Stephan

It must be a combination of these two things. I've exhausted everything else. I just did a test by holding the metal pipe that goes  into the radiator next to my amp (in effect grounding my body before I touch the guitar) and the popping problem goes away. Looks like I'm all charged up with static. Looks like I will have to attach an earth lead to myself before I play from now on lol.
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: JJretroTONEGOD on January 21, 2013, 11:34:01 PM
On all amps, all guitars (apart from the one with an emg in it) in all sockets around the house i get a hum which disappears when i touch the metalwork of the guitar.

Assuming the electric sockets are wired correctly and the amp's safety grounds are intact, a bit of hum reduction when touchng the metal parts is normal. The reason is that once you touch a metal part your body gets grounded and acts like a shield. The effect can be minimised by shielding the wiring in the guitar as much as possible. Putting covers on humbuckers also helps in that regard. However, it will not be possible to eliminate all of it since the pickups are susceptible to picking up stray noises as well, and if you shield them completely in a case you shut them off from the strings rendering them unfunctional.

The standard EMG set up does not ground the strings so you will not have the additional shielding effect by touching the strings since your body will not be connected to ground.

If you get crackling or loud popping you could have problems with static charge. This happens with guitars with plastic pickguards sometimes. Putting some aluminum foil underneath the pickguard helps and also adds shielding.

Cheers Stephan

+1 and adding to that conductive copper is also ideal for lining the inside of the guitar
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: sjwebb90 on January 23, 2013, 09:38:04 PM
Some light reading on Guitar Buzz

http://www.guitarworld.com/how-eliminate-guitar-buzz (http://www.guitarworld.com/how-eliminate-guitar-buzz.)

Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: darkbluemurder on January 24, 2013, 09:04:30 AM
That link does not work for me.

Cheers Stephan
Title: Re: Mains hum that disappears with hand contact on all my equipment.
Post by: BigB on January 25, 2013, 06:49:41 PM
That link does not work for me.

It's because of the final dot  :lol:

http://www.guitarworld.com/how-eliminate-guitar-buzz (http://www.guitarworld.com/how-eliminate-guitar-buzz)