kendall
Rookie Solder Flinger
Posts: 6
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Post by kendall on May 28, 2006 20:10:44 GMT -5
All,
I am looking for some photos or instructions, on how to shield my cheap single coil pickups with copper tape.
I understand how to shield the cavity, and pick-guard, but I am unclear about the coils.
These are the type of pickups you would fine on an entry level Strat (Squire).
The GuitarNuts website was going to post an article about this, but never got around to it.
It seems pretty straight-forward, but I am not sure which part to wrap ... or not.
Any help will be greatly appreciated.
Thanks, Kendall
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Post by sumgai on May 29, 2006 5:42:07 GMT -5
Kendall, Not highly recommended - too much chance of screwing something up, expensively so. It can be done, but most players with a properly shielded guitar will tell you that you don't need that last little bit, the tiny amount of coil that lays above the pickguard. That amounts to maybe 2 or 3% total exposure to possible hum. Knocking down the rest of the possible hum is good enough for most players in most situations. That said, you need to use a narrow piece of copper tape or foil, and you definitely need to use some kind of insulating material between the coil windings and the copper. When this is all done, you may have a pup that won't fit back into the cover. Forcing this oversize goodie to fit the cover is just asking for trouble, as you might imagine. Take your time, take careful measurements if you can, and don't force anything. If it doesn't work, it's a sure sign from you-know-who that this isn't meant to be. ;D But as they say, your mileage may vary! HTH Oh, and to the forums! sumgai
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Post by ChrisK on May 29, 2006 21:04:20 GMT -5
I've thought about this for a while. I "tend" to believe that a pickup should be shielded by wrapping the shielding around the coil without forming a shorting loop (tone robbing). This infers an insulator under the copper wrapping.
Since we tend to use copper, aluminum, and conductive paint, all most likely containing NO ferrous material, we're really shielding against electrostatic fields and not electromagnetic fields.
Mu-Metal anyone (I do have a small, private stock).
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Post by sumgai on May 29, 2006 23:36:10 GMT -5
Chris, I'm puzzled here, can you help a brother out?
While in the US Army, one of my few positive contributions during my service was that I worked on the team that wrote the MilSpec for shielding isolation rooms to be used for calibrating sensitive equipment. We tested both copper and ferrous materials for both electrostatic and electromagnetic fields, and copper came up a winner in both cases. At that, the shielding was actually not a solid material, but a true screen, about 1/20" grid. Worked well to prevent a 500 watt transmitter located 50' away from getting in to the room at all - no detectable radiation from that transmitter, be it on am, cw, ssb, fm, or fsk. I don't know about you, but I'd call that pretty successful shielding from electromagnetic radiation.
Got any links, please?
sumgai
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Post by ChrisK on May 30, 2006 17:39:31 GMT -5
The screen that you refer to is called a Faraday cage (named after Michael). The pitch of the screen is a function of the desired effect at the frequencies of interest. Many of the higher frequencies travel on the skin of a conductor (the skin effect) and are best conducted away by thinner materials of high conductivity. This is why AM radio coils are wound with Litz wire, a multi-conductor made up of pickup-sized multiple conductors. Things vary with frequency.
While copper (or any conductor) will shield against electrostatic fields, and develop induced current (and substantial field reduction from same) as a function of intercepting electromagnetic fields, a non-ferrous shield won't block magnetic fields. I covered a Tele covered neck pickup with 8 layers of alumanajim foil and, guess what, still definitive poles attract another magnet (a magnet polarity tester). This might explain why metal covered pickups still work.
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Post by bam on Jun 13, 2006 2:06:46 GMT -5
this is mine's. Sorry, but I have no spare pups and I don't want to re-open my guitar cavity again just to take another photo.. The aluminium duct tape used for shielding is connected straight to the pickguard's shield by using a band of aluminium foil. This is just enough; trust me, you don't need to order those -rather- expensive copper net.
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mikesr1963
Meter Reader 1st Class
Posts: 99
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Post by mikesr1963 on Aug 28, 2006 19:47:13 GMT -5
I wrapped mine by making my own copper strips. A couple of wraps securing it with rubber bands no sordering or sticky tape and the covers still fit with no problems.
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