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Humming WHEN(?!!?) you touch the strings..??! pls help

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Postby greg kfm » January 6th, 2009, 10:24 pm

Hi everyone!

I got a problem recently on my Les Paul.
The internal wire connections to the jack needed new solders. So i took it to a shop where the guy did some new ones.

But now, i can't even play as the humming WHEN i touch the strings is strong!! (the strings or any metal parts of the guitar)

I've heard and read a lot about grounding issues and humming when you DON'T touch the strings, but never when you actually touch them... I'm pretty sure of not being a such powerful electrical device myself :? lol, so would anybody have any idea about the why? and how to fix?

I thought maybe the guy just inverted the wires connected to the jack (a black one and a white one)...would that make that kind of effects??

thx a lot for your time!

regards
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Postby Ricochet » January 7th, 2009, 3:56 am

Yeah, it sounds like when you touch the strings you're grounding out the signal side.
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Postby Hyperborea » January 7th, 2009, 11:15 pm

In general, people are not really that great a ground especially when compared with copper wiring. So, when you touch the strings you won't be grounding out any signal unless you're standing barefoot on your copper plumbing or in a puddle on the ground. If that happened you wouldn't get a noisy signal but a loss of signal.

If the wiring was reversed by the guy in the shop then the original ground is now the signal and that includes the string ground. So, when you touch the strings you are connecting yourself into the signal side and injecting electrical noise into the signal (people are a good source of electrical noise).

Another possibility is that the string ground was disconnected and when you touch the strings they are working as aerials to help transmit your electrical noise into the guitar's signal wiring.
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Postby greg kfm » January 15th, 2009, 6:32 am

hey!

problem solved!thx

your answer was a bit complicated to me...lool...took me some time to understand the details of how electronics in a guitar work. And before going back to the store to tell them they didn't do their job :evil: , i wanted to make myself sure to understand what i was gonna talk about... :oops: lool

So they just "switched" back the wires to normal and now everything works perfectly fine, and i know stuff about guitars that i probably wouldn't have learn if i didn't have this problem!!

So..Great "Thanks"!!!!!
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Postby gnease » January 15th, 2009, 6:35 am

happy ending

really gotta wonder why they switched them in the first place.
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Postby Ricochet » January 15th, 2009, 6:58 am

Yeah, it's easy to make a simple, stupid error. Shouldn't happen, but it does. I've wired jacks and pots backward more than once. With audio taper pots, that can cause problems.
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Postby gnease » January 15th, 2009, 7:50 am

agree it's a minor, and probably common mistake -- even for those who understand the wiring. but I hope greg didn't pay too much such professional workmanship ... or someone at the shop was hot enough to make the second trip worth it. :wink:
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Postby greg kfm » January 15th, 2009, 8:43 am

loool
actually, i'm currently living in Beijing,China. and dont know any "good" places to repair guitar there... so the repair was done in a small guitar shop, for a quite cheap price ... and done by a guy who didn't really look like a professional :? . but i didn't have the choice.
He first didn't even want to admit that he made a mistake and told me that the 'hum' (which was terrible..) was normal :lol: . I had to insist to make him reverse the connections hahaha...
and no... only this guy there..nobody interesting enough to make the trip back less frustrating :lol:
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Postby gnease » January 15th, 2009, 9:21 am

interesting -- got stuck in Beijing once when I missed a connection from Shanghai back to US. Beijing ain't nothing like Shanghai.
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Postby johnlo » June 17th, 2009, 7:29 pm

Thanks! I wired my first guitar this weekend and couldn't figure out why it was humming when I touched any metal part. I unsoldered the whole thing, checked my grounds, changed the pots, tried a different amp.

I had tip and ring mixed up...

What a noob!
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Postby Ricochet » June 18th, 2009, 5:20 am

I built an amp and wired the pots backward once... :roll:
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Postby TRGuitar » June 18th, 2009, 5:35 am

Day late and a dollar short as usual (more like 6 months late) but yes, obviously the wires were backwards. I just did that when wiring my SX Strat. :oops:
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Postby Dogfacedboy » March 1st, 2010, 8:35 pm

Somebody allready answered this, but just want to interject.

The connection concerning this problem is where the cord plugs into your guitar. There are two wires there.
REVERSE them. Especially if you have had work done on your guitar by ANYONE. My connection was loose. I
pulled off the whole thing and soldered it back together (just 2 wires). When i tested it it sounded fine, ONLY because
i has amp set on CLEAN. When I got ready to rock, all good until i touched the strings. Then, "HMMMMM"!!.
Basically what i call a 'reverse ground effect', if such a thing is real. When I re-soldered them back (just 2 wires again),
the opposite way, BOOM, problem solved, and i went on to rock the nation. thank you. we love you. goodnight!!
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