• Ernie Ball
  • MusicMan
  • Sterling by MusicMan

How should shielding/electrical be done?

  • Cut around the pots. You're making a second path

    Votes: 0 0.0%
  • If you're playing Metal, all noise becomes music so who cares

    Votes: 0 0.0%
  • Route all ground wires to the shielding between pots

    Votes: 0 0.0%

  • Total voters
    7

Jack FFR1846

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Joined
Feb 17, 2008
Messages
2,176
Location
Hopkinton, MA
I was doing a complete redo on a guitar of mine with new switch, pots and a couple pickups from a silhouette spec into a non-ebmm guitar (hey, ya can't blame me for wanting to improve what I got!) and while working on it and paying attention to where all of the ground wires were going, it occured to me that the aluminum shielding on the pickguard could actually be screwing up the single point ground connection (aka star connection) that is on the body of the volume pot.

What do I mean, screwing it up? Well, the aluminum is a conductor as well as a shield. Yes, the pots have a wire from tone pot to the volume pot body. But the shielding is making physical contact to the tone and volume pot. In theory, this provides a parallel path.

On the counter side, one might argue that aluminum is not as good of a conductor as copper, so won't carry any signal (or current).......but......it's very wide of an area....like a ground plane in a pc board. So the impedance could be low.

My question is.....should we actually be cutting out sections of the shielding aluminum to avoid another path to the tone pots and switch? As maybe another alternative, should we instead solder a bare wire to each tone pot, and route it down to the aluminum shield, then up to the next pot, to the shield and finally to the volume pot?

Be as technical as you want electrically. I'm a EE

I have included a pole just to allow random answers.....
 

beej

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Joined
Aug 16, 2004
Messages
12,240
Location
Toronto, Canada
Star grounding doesn't matter in a passive guitar. There are no ground loops in a passive circuit.

As for copper vs aluminum- aluminum is a superior material for shielding so should be used when it can. (Copper is just more convenient b/c it's easier to solder to.) Fyi, here's a neat article about aluminum vs copper by Bill Lawrence:

Bill Lawrence Website
 

DrKev

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Jul 8, 2006
Messages
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Somewhere between Paris, Dublin, and Buffalo
+1 what Beej said. We only have signal and ground, and no other potentials in between. How you connect to ground, where you connect, or how many times makes, no difference.

Aluminium is still a great conductor and (certainly for these purposes) is electrically equivalent to copper. Their choice is critical circuits is often more to do with their mechanical and thermal properties, as well as cost.
 
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