Wiring help. Am I missing a wire or what?

Discussion in 'Pickups & Electronics [BG]' started by Mrmatt1972, May 4, 2018.

  1. Ok. So in a fit of irritation I decided to pull the preamp and knobs out of my Yamaha RBX JM2 because the knobs are scrathy and the preamp hisses. I figured I like the sound of the pickup so I'll wire it direct to the jack until I decide on a preamp to buy and drop in. From what I understand the pickup is a Seymour Duncan custom MM 6 string pickup. The problem is I only see 3 wires plus the shield. I thought with a humbucker there should be 4 and I would need to just twist the 2 middle wires together and wire to a jack. See images. 20180504_203521.jpg 20180504_203532.jpg
     
  2. Slater

    Slater Leave that thing alone.

    Apr 17, 2000
    The Great Lakes State
    IIRC, for a Seymour Duncan MM pickup, the red and black go together for the hot, and the green and bare go to ground.
     
    jamro217 likes this.
  3. Try to locate a wiring schematic for the pickup. That may tell you which is which. If you only have three wires they most likely are a hot from each coil and a ground. If possible, check the pickup where the wires attach and see if you locate which goes to the baseplate. That's the ground. Sorry I can't be more precise, but I'm not familiar with the hardware in question. Hope this helps.
     
    Killed_by_Death likes this.
  4. According to the Seymour Duncan site, Slater is correct in post #2. Best to you both.
     
    Slater likes this.
  5. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    That works for parallel operation, but if you want it in series...

    If you have a multimeter, measure the resistance (Ohms) between each lead:
    red - green
    red - black
    green - black

    let us know the results
     
    jamro217 likes this.
  6. Slater

    Slater Leave that thing alone.

    Apr 17, 2000
    The Great Lakes State
    I’m not positive, but I think you need a different model SD MM pickup with a fourth, white wire to do series/parallel.
     
  7. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    I'm just guessing, but I think black to hot & green to ground would put it in series (leaving the red disconnected).
     
  8. Thanks all. I wired it up passive per post #2 by #Slater. I have a bit of ground hum which I think is because my jack is old and used. It'll do for now until I order my pre. I might go for a new pickup too, but finding a 6 string MM style pickup is challenging
     
  9. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    If you have hum, maybe one of the coils isn't functioning, which would be a byproduct of wiring it up incorrectly.
    If that red wire is the center wire (between the two coils), having it connected is shorting one of the coils.

    Do you own a multimeter?
     
  10. Yes. I can do the measuring later this week i guess.
     
  11. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    Another way you can check if one coil is shorted is turn up the gain on your amp & then tap the pole pieces of the pickup with a screwdriver tip.
    If one side is much quieter than the other, that's a shorted coil.
     
  12. Slater

    Slater Leave that thing alone.

    Apr 17, 2000
    The Great Lakes State
    There should also be a ground wire from the bridge that should now be connected to the ground lug of the output jack for direct to jack wiring.
     
  13. Yeah. I know. It is. The problem is going away the more i plug in and out of the bass. I think it is corrosion on my jack (it was used and in a parts drawer in my garage for years).
     
  14. So, little update. The noise is gone, it must have been corrosion (or possibly noisy power, my town has a notoriously bad power grid). I'm finding I REALLY like it with no controls. Who'd have thunk it.
     
  15. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    You're getting more highs & more output w/o controls.

    The noisy power would have been counteracted if it was operating in humbucking mode, so I still think you might be operating on only one coil.