Hum/Buzz from les paul

[Ghane]

Hi!

Just installed a set of four conductor crawlers in my 2012 les paul along with a new wiring kit, and now a have a singlecoil like hum in my guitar. The hum completely disapere when i put my hand on he strings (or any other metal part pf the guitar)

Do i have a grounding issue?

[itamar101]

This is a grounding issue. You should check your wiring.

That said, my les paul seems to have a grounding issue that has nothing to do with the wiring. I have had it checked and rewired by three different techs and I've had three sets of pickups and there's still hum when I'm not touching any metal parts. I ended up getting the control cavity shielded, which got rid of about 70% of the hum.

It could be the bridge grounding but I'm not sure how that works.

Anyway, has the hum only started occuring after you replaced the pickups or beforehand as well?

[Dave Sloven]

Apply shielding paint to the cavities (a couple of coats, and check it afterwards with a multimeter), including the underside of the scratchplate and the control cavity covers, and check the earth from the bridge to the pots.  All of your pots should also be connected in an earth loop.

I had a problem like this yesterday.  I have to pull my SG apart again and put shielding in as the BKPs seem to have made the feedback worse, especially when I stand in front of the amp.  Also I have a much more powerful amp now than what I had when I first installed the BKPs, so I didn't notice it then, partly because it was a combo low on the floor and thus the guitar rarely got close enough to do it

[Ghane]

Resoldered the jack ground and the ground of the switch and i got rid of alot of buzz. Its still there but i guess in need to paint the control cavity with conductive paint to get rid of the rest.

Atleast its almost completely noisless now on the clean channel of my amp

[PhilKing]

Do you have a ground loop?  Make sure that there is only one way to ground from your pickups.  A favourite that causes this is taking a loop around all the pots along with grounding from both pickups.

[Ghane]

Do you have a ground loop?  Make sure that there is only one way to ground from your pickups.  A favourite that causes this is taking a loop around all the pots along with grounding from both pickups.

With ground loop do you mean if all the pots are connected to each other then yes. All four pots are connect with wire along the sides. The bridge pickup is grounded to the bridge volume pot and the neck pickup is grounded to the neck volume pot. The bridge/tailpiece  ground is soldered to the neck volume. The switch is a switchcraft with braided wire. One thing i was wondering is that the jack is only grounded via the braided wire to the switch and not soldered to a pot but that would be enough right? All the braided wires on the switch is soldered togheter and the two other wires is soldered to the neck and bridge volume pots.

[PhilKing]

I would be tempted to remove the connection across all the pots to see if that helps

[Dave Sloven]

I would be tempted to remove the connection across all the pots to see if that helps

You mean the connection between the tone pots?  My harness came wired like that.

The bridge ground is pretty much always grounded on the neck volume, that sounds right.

[Dmoney]

can you post a photo?

The backs (the shell) of the tone pots need some connection to ground otherwise they won't work.
Have you got another guitar you can compare it to?

It might sound daft but all my guitars make a little hum when I'm not touching the strings. I'm pretty sure it's normal. Maybe if you've just changed the pickups you're really aware of it now and it's actually the same as it was before now you've cut the bulk of the noise down.

[Dave Sloven]

can you post a photo?

If you are referring to mine here's a photo of the harness before it was installed.



That solder blob on the neck volume is where the neck ground wire and the bridge post ground wire attach.  There is a similar one on the bridge volume for the bridge pickup ground.

Installed (note lack of shielding):

[Ghane]

I will post a photo of my instalation to after i get back from work today.

I was thinking. My new pickups is an open set (my old was covered) and the bridge and neck volume pot are now 500k instead of 300k(?). I guess this can let a little more buzz through. When i roll the tone down the buzz is disappearing.

Maybe it is like Dmoney said, im just more aware of it now beacause i just changed pups in the guitar.

[Dave Sloven]

Grounding your instrument properly is not a joke.



 :P

[darkbluemurder]

I was thinking. My new pickups is an open set (my old was covered) and the bridge and neck volume pot are now 500k instead of 300k(?). I guess this can let a little more buzz through. When i roll the tone down the buzz is disappearing.

Correct on all accounts. The covers provide shielding to the pickups. Some Gibson Les Pauls of the Norlin era used covered pickups and encased the electronics in a metal cage which allowed them to remove the string ground. Put uncovered pickups in there and it hums like crazy. Higher value pots bleed less signal to ground (and also less of any unwanted signals). And since the buzz contains a lot of high harmonics it disappears when you roll down the tone.

What you describe appears to be rather normal.

Cheers Stephan