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Out of phase

Discussion in 'Pickups & Electronics [BG]' started by Gianni, Jun 3, 2004.

  1. Gianni


    Jul 4, 2001
    Palermo - Italia
    I have added 2 EMG J PUPs to a warwick masterman 4.
    Now the system has these 2 EMGs and a MEC Twin Jazz.
    The 2 couple of PU go to 2 PU selectors then to 2 bass-high stacked tone controls then to a balance-level stacked knob.

    I had asked to EMG if their PU could work together with the MEC.
    They said yes.

    Now: the EMG are in opposite phase with the MEC.

    Is there any solution to such a problem?
  2. Gianni


    Jul 4, 2001
    Palermo - Italia
    None has any idea? :crying:

  3. luknfur


    Jan 14, 2004
    For What It's Worth:

    I've never heard of a set of pups being out of phase with a preamp. Pups that are out of phase with each other can be corrected by swapping the pup wires. Problems between preamp and pups are typically along the lines of an impedance mismatch, which I understand can be corrected with a buffer - though I've never had the problem or done so. Sounds like you have at least one other pup in there besides the EMG's so you might try just running the EMG's and see what you get. Could be an impedance imbalance between the EMG's and other pup(s)?

    You might also have a look at EMG's wiring schemes and see if you notice any variation in the way they wire their pups to their harnesses. I've noticed on blend pots especially, some variations between manufacturers that could pose a problem and there may be something going on there. I assume you just dropped the pups in to the existing harness, but I'd look closely at any alteration, whatever they were, for the source.

    Not sure how good EMG is about their email but you might give them a shot.
  4. Gianni


    Jul 4, 2001
    Palermo - Italia
    Thank you for your answer luknfur (and also for your interesting experiments).

    The 2 EMGs work well together and so the 2 coils of the MEC twinjazz.
    but tt the ouput the 2 couple of Pups are out of phase.

    If the Pups are in origin out of phase the problem cannot be corrected swapping the wires because they are all ACTIVE and have an output wire that cannot be changed.

    It is a pity because I could try 15 different Pups combination.

    I fear that I should change the EMGs with 2 Mecs or the MEC with one EMG...

    People at EMG suggested me to change...the MEC!

  5. I think I understand what happening here...

    So you've got 3 pickups happening here? The two EMG J's and the MEC double J, each into the same preamp or two seperate pre which are then blended?

    I think what is being refered to is not the EMG pups and the MEC pre being out of phase but the EMG pups and the MEC pup. Therefore you should just have to change the wiring of one set of the pups, my advice is the MEC, from what you described the EMGs are tied up a little more in the electronics. This is just my advice without seeing whats actually happening, Luknfur is way more qualified to tell you exactly what you'll need to do, though it should just be matter of swapping where the wires that come from the MEC join to the output and ground.

    Josh D
  6. Gianni


    Jul 4, 2001
    Palermo - Italia
    1) the 2 EMG go to a PU selector, then to a bass-treble booster,
    2) the 2 coils of the twinjazz go to another PU selector an to another bass-treble booster.

    Both the signal from the bass-treble boosters go to a preamp with balance and volume.

    The original scheme in which the 2 coils of the twinjazz went each to its bass-treble booster is here:

    Now: at the output the 2 couples of PUps work well separately, but are out of phase.
    As far as I know 2 are the possibility
    1) The Pups are out of phase
    2) something in the circuit (the 2 tone boosters?) introduce a 90┬░phase rotation each other

    Now I have noticed that, although the bass-treble boosters are equal, one has a small cilindrycal component on board that the other has not.

    I think what is being refered to is not the EMG pups and the MEC pre being out of phase but the EMG pups and the MEC pup.
    Therefore you should just have to change the wiring of one set of the pups

    But these PUps are active and have a preamp INSIDE:
    the repairman says that it is not possible to swap wire, as happens with passive Pups, because they a hot wire...

    Anyway I could be wrong...

  7. Aaron Saunders

    Aaron Saunders

    Apr 27, 2002
    What about on the MEC pup? If there's a separate MEC preamp (which is the case in Warwicks, IIRC) then you can just swap the wires on the MEC pup.
  8. Gianni


    Jul 4, 2001
    Palermo - Italia
    Although in my bass they are also connected to an active preamp (as well as the EMGs), the active MECs are active PUPs like the EMGs and own an onboard preamp.

    Stephen Manz at Warwick confirmed that it is not possible to swap the wires.
    But he does not know if there is an opposition of phase between all EMGs and MECs or only my twinjazz.
    He also told me how to verify with an analogic tester.