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Shielding Question

Posted: 3 Dec 2018 6:22 am
by Fred Hedgecoth
I just thad the pickup on the old Maverick rewound (thanks Mike!) but I'm still getting a pretty pronounced 60 cycle hum. I've checked the cords and amps and all is fine with other guitars so I'm wondering if there is some shielding in order on the Maverick. The 2 leads just come through the guitar neck straight to the jack which is just screwed into the guitar as usual (see pic). Touching the strings or metal body parts does reduce the hum somewhat so I'm figuring it's me that's grounding everything. Any suggestions are appreciated.
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Posted: 3 Dec 2018 8:18 am
by Donny Hinson
You're probably going to get some hum with any single-coil pickup. But first, I'd try reversing the wires at the jack, to see if that makes any difference. You should also check your cables to make sure they're not causing the problem. I'd also check the outlets where your amp is plugged in. It could be that you have an outlet that's not properly grounded.

Do you have a (grounded) 3-pin plug on your amp?

Posted: 3 Dec 2018 10:43 am
by Brad Sarno
If it's a single coil pickup, shielding is probably a wasted effort. The shielding of the lead wires won't even address 1% of the hum which is really coming from the coil. Not much one can do about single coil hum other than get a hum bucker. Sure there are pedals that can address it, but I'm not a big fan of those things as they just seem to add more crap and processing to the signal.

B

Posted: 3 Dec 2018 11:02 am
by Fred Hedgecoth
Thanks fellas. I'm going to try a different power source and see what happens.

Posted: 3 Dec 2018 11:42 am
by Brian Hollands
Shouldn't there be a ground on the changer? Run a lead from one of the changer screws to the jack sleeve.

Posted: 3 Dec 2018 10:24 pm
by Earnest Bovine
You can get most of the benefits that a shielded cable would give you by just twisting the unshielded pair:


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but as Brad says, that wont help much because most of the noise being picked up by the pickup (why do you think they call it that?) and not by the red & black wires to the jack.

Posted: 4 Dec 2018 5:59 am
by Fred Hedgecoth
You nailed it Ernest! I braided the leads and the hum is almost gone! As I recall, the wires were twisted when I took the pickup out for rewinding. Glad it was a simple, but effective fix.

Shielding Question

Posted: 21 Jan 2019 7:27 am
by Fred Hedgecoth
Well it's been a while and looks like the pickup noise is still enough to be irritating. I tried grounding the black wire from the jack to a metal block on the guitar underside but it's still noisy. I notice that the noise greatly increases when I put my finger on the jack itself. When I take it away the noise level drops but does not disappear. I bought new cables and my other guitars are not giving me a problem. Any suggestions (other than getting a new guitar and gear!)?
Many thanks!

Posted: 21 Jan 2019 8:07 am
by Bill A. Moore
Last year when firing up an amp build on the kitchen table, It seemed to have an abnormal amount of hum. I moved a few wires, but it was still noisy. I got up to get a drink, and decided I didn't need the overhead light any more, and turned it off, noise was gone!
I had forgotten that circuit was on a dimmer!

Posted: 21 Jan 2019 8:23 am
by Dick Wood
Fred, One or two things to check. Is there a florescent light over the guitar or near it? If so,turn it off. Pick the guitar up and turn it around in a circle while it's on and hooked up which will sometimes lessen the noise indicating something nearby is generating the noise.

Years ago I installed a single coil in one of my guitars and it was very quiet at home but horrible at several venues.

I ultimately changed it out to a Humbucker and moved on.

Let me know what you find.

Shielding Question

Posted: 21 Jan 2019 8:28 am
by Fred Hedgecoth
Thanks for the replies fellas. No flourescents in the area and re-orienting didn't help...BUT I replaced the input jack, grounded the jack to the changer base and it seems to have fixed it about 95%. I think the house wiring may be guilty of the remaining 5%.

Shielding question

Posted: 21 Jan 2019 8:44 am
by George Kimery
Being a dyed in the wool single coil pickup guy, I have dealt with hum issues. 99% of the time,it is not a problem. One venue, I had to move to the other side of the stage away from a Crate PA head. Two other venues, one just had bad hum from light dimmers, and another place, just had bad electricity or maybe the ballasts in the overhead fluorescent lights. Anyway, I now go prepared. I got an EbTech Hum DeBugger and it eliminated the hum in all 3 places. I have had no problems any where else.