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Phase issues with pick ups.????

Discussion in 'Pickups & Electronics [BG]' started by Smoove-Groove, Aug 22, 2014.

  1. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    Alrighty then!

    I have been posting about an old Hondo P bass copy that I have been modding. My last problem was with hum and buzz, which magically disappeared. One problem down.
    There is a Dimarzio p pick up in neck position and I just installed a Peavey super ferrite in bridge.
    All is well, both pu's work. By themselves they sound nice. But when I flip the switch to activate both, I get a reall drop in volume on the E and A strings. D and G sound as they should,but E&A almost sound out of phase.Kinda hollow.
    Im pretty sure I wired everything right as the pu's sound fine when played one at a time.
    Could this be due to the position of the pole pieces for E & A strings on the p pickup being further away from the neck pickup,and causing a phase issue?
    Like I said earlier D & G strings sound good.
    Any thoughts/remedies on this one?????
    Last edited: Aug 22, 2014
  2. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    Yes. You are out of phase. Try flipping the hot and ground of the single coil to see if that fixes it. Better yet, get a matching Dimarzio J humbucking pickup, whether the Model J, Ultrajazz, and solve all your problems.
  3. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    Thanks! I'll give that a try. I have already routed out the cavity for the super ferrite, so the jazz would be out of the question.
    It actually sounds good. Just gotta fix this phase issue.
    Thanks again.
  4. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    I flipped the hot and cold wires on the bridge pu and now the D & G string are now coming in weaker when both pu's on???? E & A sounds good.
    A complete reversal of the original problem :laugh::laugh:
  5. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    There's a white,blue and black wire coming from the p pickup.Blue and black were both soldered to vol pot body,while I had white on 3 way switch.
    Swapped white for blue. Still no luck. D & G strings still out of phase:sour:
    Wonder if I should attach blue and white together and attach those to the 3 way switch??????
  6. JustForSport


    Nov 17, 2011
    The P is split-coil, hum-cancelling, so, which ever way you have a single-coil attached, one side of the P will be out of phase with the single-coil.
  7. flameworker


    Jun 15, 2014
    Landenberg, Pennsylvania
    one day....
    That sucks.
  8. Crater


    Oct 12, 2011
    Dallas, TX area
    No, it shouldn't work that way. One side of your split P pickup is turned around. Try to re-arrange it like this:

  9. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    Thanks for this.
    Im pretty much wired up this way, but my p pickup has 3 long wires coming from it. A white,blue and black.
    I have the blue going to the post of a 3 way switch and the white and black soldered to the pot body.I have swapped the blue and white around with no luck.
    I have also swapped the bridge posistion wires around too with no luck.
    Kinda sucks! would love to have the tonal option of both pu's at once on this bass because the 2 strings that are in phase sound good.
    Hopefully there is a remedy for this. If not I'll probably just buy a 2 way switch and have to settle with using both pu's by themselves.

    Oh..... I did do a little searching around and found someone else on another site was having a similar problem. They got a reply from someone saying that
    the pickups aren't matched impedence wise so it'll never work!
    Please say this isn't so.....would love to have this fully functioning. There has gotta be something that can be done. Don't really want to change out the Peavey Super Ferrite because it sounds really nice. There's a lot more to it than a regular jazz pu to my ears. And it looks cool too;)
    Thanks for all replies!

    Here's a pic of the beast...and the wiring

    [​IMG] [​IMG]

    [​IMG] [​IMG]
    Last edited: Aug 23, 2014
  10. JustForSport


    Nov 17, 2011
    Re: "No, it shouldn't work that way. One side of your split P pickup is turned around. Try to re-arrange it like this:"

    Just physically flipping a pickup around doesn't change the winding direction, nor the polarity.
    What makes a pickup hum-canceling is that one coil is reverse-wound and reverse polarity relative to the winding direction of the other,
    or it (if single-coil) is connected to another single-coil that is reverse-wound, reverse polarity.

    You could swap the white and black wires going to the 2nd P half, then wire the single-coil to be reverse-wound,
    but then the P would not be hum-cancelling by itself.

    Best solution may be to use a split-coil jazz p/u with the P.
    Last edited: Aug 23, 2014
  11. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    When you say swap the white and black wires, do you mean put the black on the 3 way toggle where the white usually goes(hot).
    Tried this and swapped neck pickup wires and got no sound out of the p-pickup.
    Kinda finding it hard to believe two pickups can't work together.They both sound great by themselves.You'd think they would be able to function together. Im not considering a regular jazz pu because I have already routed a big cavity for the peavey. Im not too worried about the P-pu not becoming hum cancelling if there is a way to wire it up that way.....?????
    Are the laws of electro-magnetic-kinetic-computronic blah blah blah not gonna let me have my way? ;)
    Last edited: Aug 23, 2014
  12. I don't want to be rude, but much of the information posted here seems to be misleading.

    forget about reverse winding and reverse magnets and hum-canceling for the moment.

    all three coils on your bass should have their signals in phase with each other. for you to get a phase issue on two strings, then have this swap to the other two strings when you reverse the j's wiring means that your p has its coils out of phase. a p pickup will still work solo with its coils out of phase because unlike just about every other hum canceling pickup, it's coils are not sensing the same strings.

    the fix is simple. reverse the wires on one of the p pickup's coils. if your p pickup hums when solo after you have done this, then it is faulty. perhaps it's magnets have fallen off and been put back incorrectly. I've also seen fender p pickups that have two coils with the same magnetic polarity.

    if your p pickup has four conductor wiring, then swapping the wires to one coil should be straight forward with a quick multimeter test. if your p has traditional wiring, with the coils' series connection at the pickup, then you will have to reverse the wires at the coil terminations.

    once the signals from all the coils are in phase, then you can decide whether to improve the hum situation by modifying or changing a pickup.
  13. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    IMG_00000338. Thanks for this. I'm still a little confused about swapping wires to different coils. Wouldn't I have done that already when changing the wires around. I tried many different configurations. Unless you mean changing wires on the actual pickup itself?
    A magnet from the underside did actually come off when I
    first started wiring this thing up, but it went back into place fairly easy
    Here's a pic of the underside of th p-pu. Are there any wires here that I should be changing.

    Thanks again
  14. JustForSport


    Nov 17, 2011
    That photo is not the same as the diagram...
    You can swap the outer 2 wires on either half, then wire the J to be in phase.
    If you're not really sure about your soldering abilities, use a heat sink at the pickup terminals,
    and cut, the swap the wires a couple inches away.
    Reason being, the coil wires are VERY thin, and if too much heat gets into the coil, it can be damaged.
    Better yet, snip the wires first, use alligator clips to try the results, then solder them, if that's what you want.
  15. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    So what I would be doing is putting say, the white wire in the middle solder joint of the one half of the pu, and putting the black wire where the white was?
  16. hang on just a sec.

    OK, if it went back easily, that's not right. With this type of pickup, the magnets should repel one another where they touch the bottoms of the grub screws. You actually have to put it back so there's some magnetic resistance, for want of a better description. You'll have needed some force to place it there. If the magnet just snapped back in on its own, then you'l have to pry it off and do it again, the other way 'round.

    It's not uncommon for these dimarzios to be faulty this way because the magnets can fall off, and people just place them back the wrong way around.

    If you look at the magnets in situ, the face that runs the length of the bar that mates up to the pole pieces (grub screws) is the magnetic pole. North on one edge and south on the other. On one bobbin, two north edges must be pushed together and on the other, two south edges.

    Do you remember which magnet was the one you re-glued?
  17. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    Ah ha!
    I didn't reglue it. It just kinda positioned itself when I placed it on, and stuck to the pole pieces magnetically.It's touching the screws. I noticed the magnets have a light coloured edge and a dark coloured edge. On one half of the pick up the dark edge is facing in toward the grub screws. On the side where the magnet fell off, the light side is facing in. Do I have to glue this back on so it's not touching the pole pieces? What kind of glue should I use? Hot glue gun???
    Last edited: Aug 24, 2014
  18. Yep you need to turn that magnet around. You will need glue to hold it in place because as I mentioned, if you have it correctly positioned, it won't want to stay there. It will repel from the other magnet.

    I'd use a couple of drops of super glue. But be careful not to get glue onto the grub screws.

    First I'd press the bobbin onto the bench in a blob of blue-tack so the bottom is facing up (obviously!) and it's nice and level. Then I'd poor a little pool of super glue out into a small cup of some sort. The bottom inch of a plastic coke bottle cut off and turned upside down has a little dimple that is perfect for this. Then I'd apply the glue with a toothpick or a piece of guitar string in drops so you have good control. Don't use too much glue. Just a line maybe 3-4mm in width running down the middle of the where the magnet will be, and keep it 3-4mm back from each end. Oh and wipe both the magnet and the bobbin with a light solvent like metho or lighter fluid or whatever, to really clean the gluing surfaces before you go ahead and line up the magnet.

    If you have a compass, then at the end of this you should be able to check that the edges facing away from the grub screws are the same magnetic polarity, and in turn the tops of the bobbin (where the grub screws are adjusted) is the opposite of this polarity. Then with the other bobbin, the same is true, but with the polarities reversed.

    If you then wire it correctly, this will give you hum-cancelling when the P is solo'd.
    Last edited: Aug 24, 2014
  19. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    Thanks. But..... when I place the magnet back in it's original place,
    it sticks to the pole pieces, it doesn't repel from them no matter what way the magnet is turned. I can position the magnet a tiny distance back from the pole pieces so there is maybe just under a 16th of an inch gap. But when I let go the magnet goes straight for the poles again. So I would have to glue it and put a really thin spacer between the magnet and the pole piece until it dries.
    So... would this be the remedy for the 2 strings being out of phase?
  20. Smoove-Groove

    Smoove-Groove We've got bush, We've got bush!

    Jun 18, 2013
    Ontario, Canada
    So..... I just popped out to the music store and bought a new p-pickup.
    A Seymour Duncan quarter pounder. Not too crazy about replacing a dimarzio with this, but oh well.
    I wired it up and everything works fine now. No phase issues. Im guessing the dimarzio was faulty. And the other magnet ended up
    coming off too. So I'll try and salvage them.
    Thanks to all for helping out.


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