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Wiring problem

Haven't built anything in a while, but I got a hair to build a "nice" guitar, a four-string electric. Looking for a mellow "hollowbody electric sound.

Got a nice big Las Cabrillas box...

Got everything done over the weekend and started to wire the thing up. I'd decided to use the P-Bass pickups from Gitty and followed this wiring diagram, pretty simple:

http://www.seymourduncan.com/support/wiring-diagrams/schematics.php...

Got it done, did the "tap test" on the pickups and all seemed fine. Both volume and tone worked, good signal.

I put the strings on and.... Not so good.

I'm getting a strong buzz whenever I touch the strings or the grounded tailpiece. Buzz decreases greatly when I take my hand off.

Buzz almost goes away when I hold the output jack.

Very low signal...It's there, but not loud at all. I ran it through both my amps, my little Honeytone and my Behringer practice amp.

My gut feeling is that it's a ground problem, but I followed the diagram and can't find any visible fault.

Also, the strings are quite far away from the pickups; I might have to re-do the way the PUs are mounted.

Any clues as to what to look for?

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Permalink Reply by David McQueen on October 1, 2013 at 3:14pm

Try running a ground from the master volume to the ground on the jack. That should ground out the strings, the pickup and the tone control to the same location.

Are you running sheilded cable? If not, are your cables twisted? You could be picking up some interferance with no sheilding.

Is this the pair of enclosed bass pickups wired in series that Gitty sells? If so, these are fairly high impedance at 7.75 K Ohms each. The impedance goes up when wired in series. I am using one of these in a build with both 500 K volume and tone pots. You might try bumping up your pots to 500 or 1000 K if you still are not getting good response.

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Permalink Reply by The Capo Kid on October 2, 2013 at 3:00am

First off check your wiring to see if you have stray strands of wire touching this will cause a short , and check all the earth wires and are you getting a good ground on the tailpiece ,check the jack plug as well earth to the centre , as all the pots and jack and the tailpiece are grounded together there shouldn't be a problem

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Permalink Reply by Mark Werner on October 2, 2013 at 12:52pm

I'll pull the strings off and take a good look....I was pretty sure it might be a grounding problem.

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Permalink Reply by John Sawyer on October 2, 2013 at 4:16pm

You don't have the signal/ground reversed?

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Permalink Reply by the anonymous pick on October 2, 2013 at 8:06pm

also .. don't forget the fact it may not be the guitar .. try using a different outlet (or other guitars on that one ) .. turn off the air conditioner and florescent lights etc .. and try a different cord .

before you start taking apart the guitar .

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Permalink Reply by The Phrygian Kid on October 2, 2013 at 8:47pm

Sounds to me like you have inadvertently connected your bridge to hot rather than ground, otherwise touching the strings would be the same as touching the jack

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Permalink Reply by David McQueen on October 3, 2013 at 7:23am

Looking at the diagram, it looks like the bridge and the pickup grounds run to the back of the volume pot and then don't go anywhere from there. If that is what is really ther, a ground from the pot totthe jack should help.

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Permalink Reply by The Phrygian Kid on October 4, 2013 at 5:05pm

If he'd done that then that pickups wouldn't work at all.
He's wired the strings to hot.

Mark you can get a multimeter and check your continuity from strings to the jack plug.

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Permalink Reply by David McQueen on October 4, 2013 at 11:54pm

Arrg Stupid iPad. When I look at the diagrm as it first comes up, all wires from pickup and strings end at the volume pot ground. When I blow the pic up, all of a sudden the ground from the volume pot to the other ground wire shows. Sorry about that. It lloked like it was grounded to nothing.

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Permalink Reply by Mark Werner on October 5, 2013 at 6:05am

I'm sure it's some sort of ground problem.. I thought I'd found it when I opened the box back up, as the folded over pot lead with the ground wire had pulled loose.
I tacked that down again, and....No love. Just the same as before.

I'll fiddle with it over the weekend here..... If the leads to the jack were reversed would that cause the probem?