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Odd output problem after pickup swap

Discussion in 'Pickups & Electronics [BG]' started by dave120, Nov 28, 2005.


  1. dave120

    dave120

    Jun 27, 2005
    Central Florida
    So I swapped out the P pickup in my SX P/J bass with a Seymour Duncan Hot for P bass (the bridge J is still the stock SX pickup) and here's what happened.

    It works fine when either pickup is on and the other is off and they sound normal that way. When I turn both of them on the output volume drops to about half of what it was and it gets trebly as heck. It sounds like I'm using a pick right at the bridge saddles and sounds really crappy too.

    Did I screw something up when I changed the wires? It was only 2 wires so I'm not sure how I could have screwed them up. Is this a characteristic of P/J basses wired this way? I didn't notice this type of thing happening with the stock P pickup in there before I swapped them though. Any ideas whats going on?
     
  2. Groundloop

    Groundloop

    Jun 21, 2005
    Toronto
    Sounds like you have the pickups wired out of phase, which results in the signals from the pickups (nearly) cancelling each other.

    Can you post a picture of the back of the pots so we can see the wiring?
     
  3. dave120

    dave120

    Jun 27, 2005
    Central Florida
    I'll have to take the whole thing apart again to take a picture, but all I did was replace the P pickup which is 2 wires, just the white wire and the ground wire. It's obvious which one is going to the ground (black wires) on the back of the pot so the white ones have to be the same right? I didn't modify the wiring at all just copied the way the stock pickup was installed exactly.

    Could the new pickup be wired differently internally and cause this problem?
     
  4. Groundloop

    Groundloop

    Jun 21, 2005
    Toronto
    Well, you're going to have to take the strings and pickguard off to fix it anyway, and to check to see if it looks like this.
     
  5. Different pickup manufacturers use different color coding on their wiring. This is VERY likely a phase problem.
     
  6. dave120

    dave120

    Jun 27, 2005
    Central Florida
    Ok I took it back apart again. The wiring in the bass looks exactly like that diagram for the P pickup. The black wire from the SD pickup got soldered to the back of the volume pot and the white wire went to the middle prong on the volume pot. That's the same way the stock P pickup was on and that's the same way I put the new one back on.

    Sorry for the crappy pic quality. The pot on the top is the only one that's been "changed" from stock.

    [​IMG]
     
  7. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Regardless of color coding, it sounds like the pickups are out of phase. Simply reverse the leads on the Duncan and be on your way.

    I once installed a DiMarzio Will Power Middle on a Am Hot Rodded P that I owned. The DiMarzio was out of phase with the Fender and it sounded terrible with both pups on. I then reversed the DiMarzio and was a very happy fellow.
     
  8. dave120

    dave120

    Jun 27, 2005
    Central Florida
    I guess I can try that. Is there any potential damage to my pickup if I wire it that way and it's not right? I know the black wire on the Duncan is supposed to be the ground because that's how it was installed in the other bass I had it in and on the wiring diagrams. But I also haven't worked too much with changing pickups before so I'm not too well up on phasing issues.

    So I just swap them around and it'll change the phase on it to work better with the bridge pickup you think?
     

  9. No potential damage whatsoever. Its a common problem when fitting new pickups, if only pickup manufacturers could decide on a universal colourcode :(
     
  10. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    As WezV wrote, there is nothing to worry about. Wise of you to ask though!!! As brilliant as we all are, we're not perfect :D
     
  11. dave120

    dave120

    Jun 27, 2005
    Central Florida
    Ok I took it back apart again (I don't even have to take the strings off to slide the PG out I discovered). I swapped the leads around and put it back together. I don't have a bass amp here at school, but I plugged into my brother's guitar amp long enough to make sure I still get output, and both pickups work fine both solo and together. I'm anxious to see what they sound like through my GK rig when I get home this weekend!

    I guess I'll have to swap the leads back again when I replace the bridge pickup, but I'm gonna do all the pots and stuff anyways at that time.

    Thanks for the help everybody!