Problem with Duncan quarter pounders (PJ)

Discussion in 'Pickups & Electronics [BG]' started by wolfkeller, Feb 13, 2018.

  1. wolfkeller

    wolfkeller Supporting Member

    Aug 11, 2013
    detroit
    I picked up a bass that came with Duncan quarter pounders. I pulled em and put em in something else. Here's the problem.
    The bass was fine with the pickups before I put the Duncan's in so I know there is no issues with the electronics.

    Ok, so, with just the J on, it's fine. With just the P on it's fine. If I have both on full, there is something strange with the J. The E and A strings sound fine BUT the D and G, and only those, sound super thin, as though I turned all the bass off. Again, ONLY with both pickups on.

    I wired white to the center lug and black to the pot case, like all of my basses. I did try flipping these 2 wires .the problem is gone but it now has this wierd sound, much thinner, ALMOST like there is a hint of...wah! ***????

    I've changed pups, rewired basses many, many times, never came across this issue.

    My thought was maybe the pick-up is bad, but then it should always be bad right? Totally stumped on this .
     
  2. Zoobiedood

    Zoobiedood Commercial User

    Sep 1, 2015
    Writer/Ambassador/Artist/Resident Bass Expert for Seymour Duncan
    Do you have a meter to check the DCR? Can you wire it directly to the jack to confirm this?
     
  3. wolfkeller

    wolfkeller Supporting Member

    Aug 11, 2013
    detroit
    I don't have a meter. I was thinking about wiring both to the jack. I'm now thinking it's something else as i reinstalled the pickup that was in it, same issue. Overheated pot? Sooo strange.
     
  4. wolfkeller

    wolfkeller Supporting Member

    Aug 11, 2013
    detroit
    Just wired pickups directly to the jack, no change. I'm baffled
     
  5. Zoobiedood

    Zoobiedood Commercial User

    Sep 1, 2015
    Writer/Ambassador/Artist/Resident Bass Expert for Seymour Duncan
    Well, thing is, you are saying the pickup when used by itself doesn't have this issue, just combined with the P? White is hot and black is ground, so you are correct there. Is there a diagram you are working off of? What are the controls on the bass?
    I would still be interested (if you can borrow a meter, or ask a tech at a music store to test it) and see what the DCR is. The J should be around 13.7.
     
  6. Crater

    Crater

    Oct 12, 2011
    Dallas, TX area
    These are the classic symptoms of two pickup that are out-of-phase. When both pickups are on, the bass frequencies are cancelling each other out. The solution is to reverse the leads on the P pickup.

    You should have a meter anyway if you're going to work on your basses' wiring, but it's obvious from your post both pickups are working.
     
  7. wolfkeller

    wolfkeller Supporting Member

    Aug 11, 2013
    detroit
    I got a meter, what and where am I measuring?
     
  8. wolfkeller

    wolfkeller Supporting Member

    Aug 11, 2013
    detroit
    I get what you're saying but how can it only affect the DG strings??
     
  9. Crater

    Crater

    Oct 12, 2011
    Dallas, TX area
    The 'second half' of your P-pickup is out of phase.
     
  10. wolfkeller

    wolfkeller Supporting Member

    Aug 11, 2013
    detroit
    Ok, how can only half of it be out of phase when it's the two coils wired directly together?
     
  11. Zoobiedood

    Zoobiedood Commercial User

    Sep 1, 2015
    Writer/Ambassador/Artist/Resident Bass Expert for Seymour Duncan
    The easiest way to describe it is in a video. Here are several.

    This was a thought, too. I suppose it is possible. One way to test, is to reverse the hot & ground of the P pickup. If the E & A strings are now the weak ones, we found the problem. And if this is the case, it would require reversing the hot & ground of the wire connecting the 2 coils. Delicate work.