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Pickup Wiring/Phase Issues Z90s

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by thesedaze, Mar 30, 2005.

  1. thesedaze

    thesedaze Member

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    Hey guys,

    I was playing on my pals SG today that houses 2 Harmonic Design Z-90 pickups. The neck pickup was playing beautifully...everything sounded great...Bridge pickup, however, seemed like the phase flipped completely and the speakers were firing backwards. Lost all fullness and seemingly lost output (I realize the output was probably still there, but due to some sort of phase issue it was being hidden).

    I haven't done any guitar tech work in regards to pickup install, so I'm not even the slightest familiar with phase issues.

    Is this even the case?

    If so, is there a way to have both pickups in proper phase or is it some sort of necessary evil to have one of them out of phase?

    How do I fix such a matter?

    Thanks
     
  2. Clorenzo

    Clorenzo Member

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    If you're talking about the bridge pickup on its own, it can't be out of phase, phase is relative and you would only notice two pickups being out of phase when both are on simultaneously. The problem here could be pickup height (it may be too low) and/or having a set where the bridge is overwound to compensate for the narrower range of string vibration there, where they were installed the wrong way round, bridge pu at the neck and vice-versa. If both pu's are identical, it's normal to have lower output from the bridge one. All you can do is play with pickup height to get the best possible balance.
     
  3. thesedaze

    thesedaze Member

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    It's not output....it's not height....& both pickups are different. I'm not necessarily saying it's out of phase in relation to the neck pu, but it was sounding out of phase with the amp...speakers firing backwards,etc.
     
  4. Clorenzo

    Clorenzo Member

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    It can't be out of phase with the amp, it can only be out of phase with another pickup on the same guitar or, if it's a humbucker, one coil can be out of phase with the other coil. The speakers can't "fire backwards", they fire alternatively forwards and backwards, it's AC.

    If you have a stereo, simply swap the + and - wires on both speakers (so that they are still in phase with each other). You've just flipped over the overall phase of the system 180 degrees. Hear a difference? Nope, the ear doesn't detect absolute phase changes. Well, there are people who claim they hear a very subtle difference, that's why some "audiophile" (ahem) CD players have a phase switch. But what you're talking about is a very noticeable effect that must be due to something else. You say that the two pickups are different, so don't rule out the possibility that they are in the wrong position. Not difficult to swap them and see what happens.
     
  5. thesedaze

    thesedaze Member

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    I have a +/- phase switch on the back of my amp...I can entirely hear a difference when the amp isn't in proper phase w/ the speakers.

    The guitar issue at hand sounds identical to the amp being in improper phase.
     
  6. Clorenzo

    Clorenzo Member

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    Ok then, swap the hot and ground pickup wires.
     
  7. thesedaze

    thesedaze Member

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    thanks, i'll give an update.
     

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