My acoustic has a ground hum.....

HardCore Troubadour

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Goes away if I touch the cable at the jack and the strings at the same time.

I know what I would do with an old Les Paul etc. but I am not exactly sure of the best way for me to ground an acoustic??

I would really hate to pay someone to ground it if it is something I can make happen.
thanks in advance,

HCT
 

Roxy13

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Just curious if you've checked the soldered joints at the jack?
 

BadPenguin

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I am assuming you have an under the saddle pickup. So....It's missing that ground link between the strings and ground. What I have found that works semi easily is grounding paint applied to the inside of the guitar under the bridge, then a ground wire sent to the ground on your output. LOTS of paint! Making sure that the holes have it too. Let it dry, then add the ground to the output, and all should be silent.

Another option would be copper tape under the bridge, making sure the string ball ends touch it. Then to ground. I prefer the paint method since it doesn't wear away as quickly at the tape tends to.
 

HardCore Troubadour

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good info...I have not checked anything yet....went to a jam last weekend, plugged it in and HUUUUUUMMMMMMMM. just enough to aggravate the crap out of me.....dead silent when I put my hands to it....good thing I brought a spare guitar.

I will check the jack first.....I have NO IDEA how I would paint the underside with anything etc. etc. Mirrors?
How does the wire connect to the paint?
 

Freddy G

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Sounds like a torn sheilding wrap on the under saddle piezo transducer.
 

Freddy G

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shielding paint? copper foil? inside an acoustic? NO.

The system should be completely self shielded....right from the UST, the shielded cable to the endpin jack.

No...something is wrong.
 

the great waldo

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Goes away if I touch the cable at the jack and the strings at the same time.

I know what I would do with an old Les Paul etc. but I am not exactly sure of the best way for me to ground an acoustic??

I would really hate to pay someone to ground it if it is something I can make happen.
thanks in advance,

HCT
What pickup system are you using ?

Cheers
Andrew
 

HardCore Troubadour

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it is the stock pre-amp etc that came from the factory....Fishman.

Gibson Songwriter Deluxe Ovankol

@Freddy G would you think can I look with a mirror and see that the shielding is torn etc?

I have an electrical background so I get it...I also have big forearms (remember, I am really a drummer), and wonder if I should just take it somewhere?
 

Freddy G

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it is the stock pre-amp etc that came from the factory....Fishman.

Gibson Songwriter Deluxe Ovankol

@Freddy G would you think can I look with a mirror and see that the shielding is torn etc?

I have an electrical background so I get it...I also have big forearms (remember, I am really a drummer), and wonder if I should just take it somewhere?
I was referring to the foil wrap on the transducer itself. Pull the saddle, lift the transducer out and inspect it. Plug the guitar in while it's free like that and see how it behaves when you touch the transducer. Make sure the transducer's foil wrap also has continuity with the shield of the cable it's attached to. Lastly you might have to pull the endpin jack an open it up to make sure connections and continuity are solid.
In order to get the endpin jack in and out of the guitar just stick a long shafted screwdriver into where you plug in the jack and use that to be able to fish it to the soundhole where you can grab it with your meat hooks!
 

the great waldo

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If the fishman pickup sheilding is damaged you can put a thin layer of ali foil over it to screen it. It might have some damage at the connection where the wire goes into the pickup. If thats the case a new pickup would be the best way to go. If it's one of the fishman coaxial pickups i'm not sure if that'll work. I'm not sure what Gibsons using these days.

Cheers
Andrew
 
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HardCore Troubadour

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the wire is fine going into the transducer.....I did a quick fix by soldering a wire from the body of the jack and wrapping it around the high E string ball. got rid of 95% it.

I did not see any signs of problems with the shilding.

I will try to find a Luthier near me, but that has been a little difficult.
 

the great waldo

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You won't always see a shield problem with a ´fishman pickup. You can attach some copper screening foil under the bridge with a thin wire soldered to it and push a bridge pin from inside the guitar through the bridge pin hole. This will push some of the copper foil inside the bridge pin hole enough to make a connection with the ball end of the string. Don't forget to attach the other end of the wire from the copper tape to the ground/earth on your jack socket. Watch out with elixir coated strings as they might be electrically isolated (you can check this with a continuity meter)
Cheers
Andrew
 

moreles

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I'd hate to rely on anything as iffy and delicate as some of the possible fixes mentioned. Hopefully, you'll find something like what Freddy suspect and be able to make a proper fix. I know I'm in the minority, but I resist installations, maintenance, and repairs that compromise the basics of an acoustic guitar. Screw with the bridge plate? Anathema, to me. I'd either make the full repair or replace the system. If the acoustic properties of the guitar are not significant in your setup and music (I've seen Pete Townsend do Pinball Wizard on a J200, and the acoustic quality was not relevant, really) then who cares, really... there's always the new Acoustasonic Strat. Good luck with the issue. I am innately resistant to anything with teeny parts that are not serviceable.
 


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