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dummy coil, revisited

Discussion in 'Pickups & Electronics [BG]' started by wilser, Jul 6, 2005.

  1. Hello,
    I have been searching for dummy coil information and came out almost empty. I know it's a coil without a magnet and it's supposed to make a single coil (or humbucker) quieter. How is it connected (series, parallel)? and should it have the same (or near) impedance as the original coil (or humbucker coil combined)? I understand that it doesn't matter where the coil is located and some even put it in the control cavity. I guess that means it doesn't matter what size the coil is?

    Thanks for any info provided.
  2. dave251

    dave251 Wendler Instruments

    Feb 5, 2004
    Lawrence, KS
    For a second coil to be humbucking, it must have the same WIRE LENGTH in the same GEOMETRY of it's sister coil.

    This is often confused with both coils having the same number of windings....

    What you have in the humbucker is essentially two radio frequency antennas, wound(or wired) out of phase with each other. You can hook them up either in parallel or series, with tonal/volume response being effected.

    A stacked coil humbucker can have nearly the tone of a single coil, but with greater output and less noise than with the use of a dummy coil.

    Pickups are one of those devices where one change effects everything else, so it's difficult to predict what the outcome will be unless you experiement, ie, do a bunch of detailed testing.
  3. Rodent

    Rodent A Killer Pickup Line™ Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Honey Badger Pickups & Regenerate Guitar Works
    Hi Wilser,

    I'm still digging for info as well, and it looks like we're tied at the score of 0 - 0 :meh:

    The closest I've come to having a solid lead is that Alembic uses these on their high end basses, and they have configured the dummy coil into their pre-amp somehow. That's where my last nugget died on the trail.

    If I uncover anything further, I'll definitely pass it along to you.

  4. Tim__x


    Aug 13, 2002
    Alberta, Canada
    For best results the coil must have a matching coil geometry as Dave251 said, and a matching impedance including inductance, this means your dummy coil should be built like your pickup but instead of magnets it should have someother ferromagnetic material with a similar permiability, position is not all that important but orientation is, it should be oriented the same way as the 'real' pickup. It seems a humbucker would be easier.