Shielding for P90s

Discussion in 'Pickup Joint' started by Davis Sharp, Oct 20, 2018.

  1. Davis Sharp

    Davis Sharp Squier-holic

    Jan 7, 2016
    Maryland, USA
    True or false - shielding P90 cavities on an LP Special doesn't make sense unless I shield the inside of the pickup covers.

    Has anyone tried that?
    1540094072115.jpg
     
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  2. daan

    daan Squier-holic

    Oct 21, 2013
    Twin Cities
    I shielded a P90 SG, I used copper foil on EVERYTHING (and even poured shielding paint down the wiring hole (rolleyes) It wasn’t any quieter afterwards, than stock with not a single bit of shield. I never thought to do the inside of the cover, though...Maybe try a spare cover first to see if the shielding changes the sound first?
     
  3. Davis Sharp

    Davis Sharp Squier-holic

    Jan 7, 2016
    Maryland, USA
    Decided to jump in. I figured that I don't need to shield the sides of the cavity if i do the inside if the cover. There is an unshielded strip running down the center, but it's not like you shield the covers of a regular single coil.
     
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  4. duceditor

    duceditor Dr. Squier

    Age:
    71
    May 29, 2014
    The Monadnocks, NH USA
    Funny, but I've never in my 50+ years of using them found P90s to be especially noisy.

    To the extent I've thought about it I've just assumed that is because they have a pretty high output and that the S/N ratio was therefore adequate.

    Or maybe I'm just not fussy enough. ;)

    -don
     
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  5. Davis Sharp

    Davis Sharp Squier-holic

    Jan 7, 2016
    Maryland, USA
    It's the N that matters, not the S:N.
     
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  6. dtsreiuqs

    dtsreiuqs Squier-Meister

    493
    Oct 18, 2015
    France
    You're right daan : it comes from the magnetic captation window, which is very large on P-90 and Mosrite PUs, conversely to Strats and Tele. These wider and flatter coils are more sensitive to hum than narrower ones.

    Unless you use µmetal shielding which encases completely the coil except the poles, chances are that any other shielding would not give a tremendous improvement. o_O

    But nonetheless, it's worth to shield the coil anyway, even if it's not µmetal : it will always stop the influence of other adverses electric noises.

    Let us know Davis Sharp if you note any improvement, and in which conditions : it's always interesting to know... ;)

    A+!
     
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  7. duceditor

    duceditor Dr. Squier

    Age:
    71
    May 29, 2014
    The Monadnocks, NH USA
    I suppose if one plays very loud in a bedroom type situation noise is all that counts, not signal/noise. And yes, in the studio. (although such are usually completely free of noise sources) But in a normal working environment?

    Well no P90 ever created an issue for me there anyhow. Neither at club or concert levels, nor in the studio. And that was back before noise canceling circuits.

    -don
     
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  8. Davis Sharp

    Davis Sharp Squier-holic

    Jan 7, 2016
    Maryland, USA
    Will do.
     
  9. DrBeGood

    DrBeGood Squier-holic

    Dec 9, 2014
    Sutton QC, CANADA
    Forums are good to let us know we have tremendous existential problems, we would never have imagined before.

    Love it ... o_O
     
  10. squierTony

    squierTony Dr. Squier

    Age:
    45
    Jul 4, 2012
    MAUD Oklahoma
    My p90s seem quiet. I've been playing mine some today and haven't noticed any noise. 20180129_180534.jpg
     
  11. Afrika61

    Afrika61 Squier-Nut

    Intresting question.
    I purchased a set of these a while back:
    irongear-alchemist-90-humbucker-sized_360_cca9c79db7dad5d8805ea223870085eb.jpg
    IronGear specifically recommended shielding as they were a single coil. I'm guessing that the steel case and base plate, which are soldered together, offer no shielding?
     
  12. dtsreiuqs

    dtsreiuqs Squier-Meister

    493
    Oct 18, 2015
    France
    No, Afrika61 : of course the encasing of these pickups offers shielding !

    It protects with efficiency against statics, capacitive adverse noise fields, appliances wires carrying 50-60hz radiations, PWM supplies and inverters that are present in many home and (indeed) industrial equipments.

    It doesn't or poorly protects against magnetic radiations, typically those delivered by transformers, adapters, which generates 50-60hz magnetic fields that can be received by the wide captation windows of large flat coil pickups, despite their encasing, which can help indeed, but can be inefficient if the magnetic perturbation is notable and the pickup very sensitive to it...

    This magnetic adverse field can be observed sometimes on speakers vs. power transformers in some combo amps. The amp is powered, the speaker gently hums but it is disconnected from the amp : it is induced by the transformer due to its magnet which capts and transfer the field of the transformer to the moving coil. The same issue can be noticed between the transducers of the spring reverb, the output transformer vs. the power transformer, and you guess that their relative placements must be studied...

    A+!
     
  13. wonkenstein

    wonkenstein Squier-Nut

    830
    Feb 3, 2017
    NH
    I have never shielded (or had to shield) P90 guitars I have worked on. Period correct Gibsons use single conductor leads with a braided shield to the pickup switch and from the switch to their respective hot connections at the pots and the output jack, the braided shield always being grounded. These guitars are usually pretty quiet unless you're aiming the pickups at something just a couple feet away that will generate 60 cycle hum. Both pickups would typically be the same polarity, too.

    But I will mention that a customer wanted his Fender Jazz Bass to be quieter than it was and there was no shielding anywhere in it. So, I put copper shielding tape inside the control cavity as well as in both pickup cavities. Then I put a layer of copper shielding tape around the inside of the pickup covers that would face the bare pickup coil but left the top of the cover where the pole pieces would come through alone. It definitely was quieter, but again because of the single coils if you're close enough and aimed at something that will generate the 60 cycles, you'd get it to hum.

    Another thing to consider - two single coils, with one of them being reverse wound, reverse pole would give you the humbucker effect when they're both on.
     
  14. wonkenstein

    wonkenstein Squier-Nut

    830
    Feb 3, 2017
    NH
    I'm also curious to see what you think of the pickups and how this guitar sounds to you after the shielding.... like do you perceive any bit of the highs missing at all? Keep us posted on what you find when you're playing it.