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Shielding pickups

9/1/2002 11:06 PM
Steve A.	Shielding pickups For a few years I was shielding all of my single coil pu's with copper foil tape (usually after dipping them in melted paraffin for about an hour). Not wanting to put the copper foil directly on the coils, I had some white rayon adhesive tape that looked exactly like the black stuff used by SD (only white). On a few of my guitars I went "hog wild" and even grounded out all of the pole pieces that showed no continuity with the windings. The end result (with the cavities shielded and star grounding techniques used) was a major reduction in noise for single coil pickups, but there was a noticeable loss of high frequencies (maybe like adding a 47pF cap to ground). Since then I've wired up a few guitars without the shielding the coils and they don't seem to be any noisier... I suspect that most of the noise will enter through the top of the single coil pickup anyway. One tip if someone decides to shield their coils: don't use an adhesive tape like I did! I have a hunch that if I ever tried removing it I would tear some of the coil wires. Mark Hammer has suggested using plumber's teflon tape for insulation and I think that would work great. Personally, I think it's pretty insignificant and not nearly as relevant as using quality leads with a seperate shield which is left floating at the pickup end (i.e. shield is not connected to coil in any way at pickup). Some people have mentioned that using shielded cable can also cut some of the highs. I've measured something like 40pF per foot with shielded cable. If the control and pickup cavities are shielded you can get away with just twisting the leads tightly, or you can wrap an insulated wire around the twisted pair for additional shielding. --Thanks! Steve Ahola

9/1/2002 11:06 PM

Steve A.

Shielding pickups

    For a few years I was shielding all of my single coil pu's with copper foil tape (usually after dipping them in melted paraffin for about an hour). Not wanting to put the copper foil directly on the coils, I had some white rayon adhesive tape that looked exactly like the black stuff used by SD (only white).

    On a few of my guitars I went "hog wild" and even grounded out all of the pole pieces that showed no continuity with the windings.

    The end result (with the cavities shielded and star grounding techniques used) was a major reduction in noise for single coil pickups, but there was a noticeable loss of high frequencies (maybe like adding a 47pF cap to ground).

    Since then I've wired up a few guitars without the shielding the coils and they don't seem to be any noisier... I suspect that most of the noise will enter through the top of the single coil pickup anyway.

    One tip if someone decides to shield their coils: don't use an adhesive tape like I did! I have a hunch that if I ever tried removing it I would tear some of the coil wires. Mark Hammer has suggested using plumber's teflon tape for insulation and I think that would work great.

Personally, I think it's pretty insignificant and not nearly as relevant as using quality leads with a seperate shield which is left floating at the pickup end (i.e. shield is not connected to coil in any way at pickup).

    Some people have mentioned that using shielded cable can also cut some of the highs. I've measured something like 40pF per foot with shielded cable. If the control and pickup cavities are shielded you can get away with just twisting the leads tightly, or you can wrap an insulated wire around the twisted pair for additional shielding.

--Thanks!

Steve Ahola