Replacing P/Us In my PRS CU22 & Swapping of Magnets

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by Matt F, Sep 9, 2006.

  1. Matt F

    Matt F Member

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    I have a PRS CU22 W/ 5 way rotary that I am going to be installing Lollar Imperial 4 conductor pickups in. I posted this on the BAM forum but I wanted to know if changing the polarity of a magnet in one of the pickups is necessary? Here is the great response I got from a BAMmer:
    http://forums.birdsandmoons.com/forum/showthread.php?t=30732

    What are yall's thoughts. I just hate to cut open a pickup if I don't have to..

    Thanks,
    Matt
     
  2. Clorenzo

    Clorenzo Member

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    You don't have to if you don't mind installing one of the pickups rotated 180 degrees, i.e. the neck pu with the screws towards the bridge or the bridge pu with the screws towards the neck. Then you would wire the other pu (the one in the normal position) as per Jim's instructions in the BAM thread (BTW Jim is also one of TGP's resident electronics experts) and the turned-around pu as follows:

    The Lollar green goes where the PRS white is.
    The Lollar black goes where the PRS black is.
    The Lollar red+white goes where the PRS red is.

    That will achieve exactly the same result as flipping one of the magnets.
     
  3. Matt F

    Matt F Member

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    That's awesome. Jim seems to really know his stuff.. And I was ready to break the solder joints on the cover and figured I would aske again before I did it.. Cool. I don't mind the screws mis matched so that's what I'll do :) Thanks alot Clorenzo!

    Matt
     
  4. Jim Collins

    Jim Collins Member

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    If you do not want to flip a magnet, and you still want to position your pickups in the standard manner (neck pickup's adjustable pole pieces pointing toward the neck, and the bridge pickup's adjustable pole pieces pointing toward the bridge), you can still get the five original sounds, as long as you don't mind the fact that the middle three sounds are not hum cancelling. To do that, connect the two pickups up in the following fashion:

    Bridge pickup: Lollar red+white = PRS red; Lollar green = PRS black; Lollar black = PRS white.
    Neck pickup: Lollar black+green = PRS red; Lollar red = PRS black; Lollar white = PRS white.

    This does not require a magnet flip, and both pickups are mounted in standard fashion. However, only the two outside sounds are hum cancelling (full neck pickup and full bridge pickup).

    Most people I talk to want all five sounds to be hum cancelling, so they don't want this option. However, since your pickups are covered, you might consider it, if you don't want to mount one of the pickups backwards.
     
  5. guitardude5

    guitardude5 Member

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    Any thoughts on flipping the pickup changing the tone... Are they wound differently at each end of the pickup? The high strings are now sitting above where the low E should be and the low E is sitting where the high E should be. How will that alter the voicing?
     
  6. Jim Collins

    Jim Collins Member

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    It isn't that the pickups are different at either end, it is that the two different coils are picking up string vibrations at different points. With a neck pickup mounted in the normal fashion, the adjustable pole piece coil picks up the strings closer to the neck, and the stud coil picks up the vibrations closer to the bridge. When you mount the pickup backwards, the adjustable pole pieces pick up the vibrations closer to the bridge. If the adjustable pole pieces are sitting higher than the stud pole pieces, the pickup might take on a somewhat brighter tone. If the two coils happened to be wound differently -- as in a Fralin Unbucker -- mounting the pickup backwards might give you an even more pronounced difference. (I'm speculating on that -- I've never used Unbuckers.)
     

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