Ground Buzz Question

[Rick M]

I've got a duel humbucker guitar that always has a low level (not that low) buzz no matter which position I have the selector switch in. When I hold the metal ferrel of my instrument chord where it exits the guitar, the buzz stops completly and the pick-ups are perfectly silent. It seems like a ground problem??

None of my other guitars do it, and this guitar always does it no matter which amp I use so I'm sure the issue is within the specific guitar.

Thanks in advance.

-Rick

[hooglebug]

yes it is a ground problem. does it buzz more when you touch the strings? if so then its probably the ground to the bridge. i had this problem with a bass. i put a small screw in the control cavity and took the ground from the bridge out and put it to the screw and that worked. its probably not the right thing to do but it worked for me. the bass has no buzz at all now.

someone else will probably have the right answer though

[Rick M]

thanks for the post - it buzzes the same - touching strings or not.

[hooglebug]

o. then i guess just go over everything and check it. check that everything thats meant to be grounded is and that all the contacts are clean

[Robert_the_damned]

If it buzzes the same if you touch the strings or not and stops buzzing when you touch another 'grounded point' such as the jacket on your cord plug then it'd be my guess that this guitar doesn't have a string ground. I'd say you need to ground your bridge. What guitar is it?

Robert

[JoeAArthur]

thanks for the post - it buzzes the same - touching strings or not.

If this is true and the guitar gets quiet when you touch the grounded metal of the plug, then it's a shielding problem - and you do not have a string ground.

I'm assuming your guitar is of the SG or LP style - like a stop tailpiece and TOM bridge. (Dang I hate it when people don't say what kind of guitar it is )

You could put in a string ground. That would require drilling through the body from the control cavity to either the bridge or tailpiece posts.

Since you have humbuckers, those wires going to the control cavity are shielded. Hopefully if you have an LP style, the wires running to the pickup selector and back to the control cavity are also shielded. Both of these being true, I would get some copper shielding foil, remove the controls (probably could work around them and not have to unsolder everything) and completely line the control cavity and the back plate with the foil. Once you put the controls back in, you need to solder a wire from the back of one of the pots to the foil to ground it.

If you have a Strat style guitar, you can put in a string ground by running a wire from the back of the volume control to the tremolo spring claw.

[Rick M]

Thanks for the Post.

Yeah, I almost mentioned the guitar but figured it didn't matter - shows what I know. It's LP style, late 70's, set-neck - unbranded but I'm pretty sure it's an Ibenez or Penco lawsuit guitar. I just bought it. The stock buckers hummed and buzzed something fierce. I swapped in a match pair of "dirty dog" humbuckers (ebay guy that make screaming pups - I've bought several from him).

The new pick-ups are two wire and have a braided shield. I souldered the braid and one lead to the pot back and the other lead to the tap on the pot.

I'm not sure what "stop tailpiece and TOM bridge" means but it looks just like a les paul in the bridge area.

It's not apparant (no braided covering) if the wires from pickup selector and back to the control cavity are shielded.

If I run a string ground, do I need to foil the cavity? Can I test the string ground by running a lead from the bridge(?) to where? one, or both of the volume pots? Or do I need to do the whole cavity foil thing?

Thanks again.

-Rick

[JoeAArthur]

Thanks for the Post.

Yeah, I almost mentioned the guitar but figured it didn't matter - shows what I know. It's LP style, late 70's, set-neck - unbranded but I'm pretty sure it's an Ibenez or Penco lawsuit guitar. I just bought it. The stock buckers hummed and buzzed something fierce. I swapped in a match pair of "dirty dog" humbuckers (ebay guy that make screaming pups - I've bought several from him).

The new pick-ups are two wire and have a braided shield. I souldered the braid and one lead to the pot back and the other lead to the tap on the pot.

I'm not sure what "stop tailpiece and TOM bridge" means but it looks just like a les paul in the bridge area.

It's not apparant (no braided covering) if the wires from pickup selector and back to the control cavity are shielded.

If I run a string ground, do I need to foil the cavity? Can I test the string ground by running a lead from the bridge(?) to where? one, or both of the volume pots? Or do I need to do the whole cavity foil thing?

Thanks again.

-Rick

"stop tailpiece" is the bar behind the bridge where the strings attach. TOM is short for Tune-o-matic.

Running a ground wire means that while you are playing you won't get the noise - just like touching the metal plug end. Take your hands off the strings and it will come back. The reason the noise goes down is because when your body is grounded - either by touching the strings or the jack, your body is acting like a shield. In the older days this was all the shielding that was applied to a guitar.

If you shield the cavity, then the foil is taking the place of your body and you really won't need a string ground. It would be easier than drilling through to the bridge as you would have to remove the posts that they mount into and insert the wire so it makes good electrical contact with it.

The return wire should be soldered to the output jack and you can should be able to tell if it is braided there. If the wires from the pickup selector to the control cavity are not shielded, I would replace those first and see how that helps - it might be all you need to do.

[lovekraft]

If you shield the cavity, then the foil is taking the place of your body and you really won't need a string ground.

Have you had success with that? I understand that it works perfectly in theory, so maybe it's just my shielding practices, but in real life I've always had better results with shielding and a bridge ground ( on passive pickups, anyway). What's your secret?

[JoeAArthur]

If you shield the cavity, then the foil is taking the place of your body and you really won't need a string ground.

Have you had success with that? I understand that it works perfectly in theory, so maybe it's just my shielding practices, but in real life I've always had better results with shielding and a bridge ground ( on passive pickups, anyway). What's your secret?

Well, yes I have had success with it but I don't have a secret that I know of... I do use a string ground for any guitar with a single coil pickup as well as open coil or coverless humbuckers.

I do use copper foil - always for shielding the cavities and covers. Some existing shielded wiring between cavities like from the control area to the pickup selector on an LP style can be crap and that gets replaced with better cable.

I've got three guitars without string grounds - simply because they didn't have them when I rewired them and I didn't care to drill for one. All are very quiet. When I do touch a ground there may be a pop, probably due to static, but when I remove the ground there is no increase in noise.

I do whatever works in practice - even if I can't explain exactly why it works.