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Post by mikeyd on Apr 26, 2021 6:17:59 GMT -5
I'm about to start my first build and wondering about shielding. I understand it helps with noise reduction, and wondering if folks recommend using paint on the cavity, or that copper tape, or something else? I noticed my actual Fenders don't have this other than some under the pickguard stuff. Thoughts?
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Post by Peegoo 🏁 on Apr 26, 2021 7:24:08 GMT -5
Shielding paint works, as does copper tape. Many copper tapes claim to have conductive adhesive that ensures electrical continuity between layers, but it often breaks down and continuity is lost. I always add a dot of solder at each seam to ensure this continuity is not lost. Where you add these little solder connections does not matter because ground loops in a passive guitar circuit are not a concern (some people believe they are and that is incorrect). Bottom line is once all your copper tape is installed, test across it with a meter to make sure you have continuity. Next step is to ensure the shield is connected to circuit ground, and there are several ways to do this. Some builders rely on a tab of the foil that extends under a pickguard screw, intended to make physical contact with the foil on the back of the pickguard, like this:  I prefer a short ground wire soldered to a ring terminal that gets screwed through the copper tape or shielding paint into the wood somewhere in the control cavity. The other end of the wire is soldered to circuit ground. |
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Post by funkykikuchiyo on Apr 26, 2021 9:30:48 GMT -5
Copper tape is more effective and easier for most DIYers... why the paint is sold for DIY stuff I have no idea. That said I've never tried the paint myself, so maybe it is a "don't knock it until you try it" sort of thing.
Your Fenders might have shielding paint hiding in there. A giveaway is if there is a random lug screwed into the wood with a wire soldered to it. Those exist to ground the paint.
Ditto on what Peegoo says about the solder dots. Also, contrary to popular lore, redundant grounds will not create ground loops. Guitar circuits aren't complicated enough for ground looping to happen.
It will reduce noise, but you have to know what to expect. Very broadly speaking, electric guitars will be noisy in two ways. The first is 60hz hum: the classic single coil hum caused by electromagnetic interference from a variety of electrical devices, given that we're an AC current sorta place. The second is the RF, and other stray noises. This is the more static-y noise that you might hear a little but goes away when you ground the strings by touching them. Shielding does not do anything for magnetism, so the 60hz hum won't be touched at all. The shielding nay-sayers usually are listening to that sort of hum and hearing nothing. For the latter, you can virtually eliminate the noise entirely with careful shielding. I say "virtually" because it can go down below the noise floor of most guitar amps. Sometimes people who plug straight into computers will still have some noise.
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Post by Auf Kiltre on Apr 26, 2021 9:37:59 GMT -5
I have shielded several guitars using copper tape, I have checked my work by using a meter to make sure I have continuity throughout. I haven't really gigged out in years so my playing is typically relegated to in home recording. My experience is the type of noise that usually is bothersome isn't solved by shielding. It's the variant that is solved by swiveling in a chair until I find that lowest noise position. If this type of interference is supposed to be resolved with shielding then I'm doing something wrong. I suspect my only solution is to build a Faraday cage in my home studio. Or use humbuckers.
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Post by funkykikuchiyo on Apr 26, 2021 9:48:12 GMT -5
Auf - you're doing it right.
The problem is that the 60hz hum comes from magnetism, a byproduct of certain devices running with high electric currents, sort of the opposite phenomenon of creating eddy currents (excuse my non-technical electrical engineering terms). You can't shield magnets, at least not in any non-lab way. If you could, then you could take a high powered neodymium magnetic, and as long as it was behind a sheet of copper it wouldn't work. Except, it does work just as well as if the sheet wasn't there.
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Post by ninworks on Sept 3, 2021 10:10:15 GMT -5
I have shielded a couple guitars with copper tape and gotten the exact results I was after. Both of them had static issues when either touching or dragging a finger across the pickguard, or as in my Gibson Les Paul Gold Top Reissue, the front of the body. The shielding completely eliminated the static issues. I even shielded the back side of the pickguard and ran a ground wire to it on the Les Paul just for added insurance. I wasn't looking for hum elimination but the shielding may have helped that a little.
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Post by ninworks on Sept 4, 2021 11:12:13 GMT -5
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Post by Auf Kiltre on Sept 4, 2021 15:07:50 GMT -5
I believe my copper shielded guitars probably have some dried blood in them. 😄
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