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Multiple wiring problems, please offer suggestions or help

Discussion in 'Pickups & Electronics [BG]' started by Groovecenter, Jul 29, 2003.


  1. When playing, if my finger hits the pole piece on my Dimarzio Ultra Jazz five pups, there is a massive amount of buzzing. The thing is, it only happens with the pole piece closest to the treble side, not the other one sensing the D string. I grounded both the green and the grey wire's from the ultra jazzes, everything else is grounded except for the bridge, which I couldn't get the solder to stick too. The buzzing stops if I touch the pole piece and another metal part of the bass excluding the bridge or strings.


    Also, I don't know if this is normal or not, but output drops as you pan toward the center of the pickups in the blend knob. Once there, the output is noticably lower than panned to either full bridge of full neck.

    there is a trebly hiss that dissapears completely when I touch a metal part of the bass (excluding the strings or bridge), any clues on how to get rid of that.

    Sorry for the long post and thanks in advance for any help you can offer.
     
  2. First problem about the buzzing when touching, I'm not fully down on the reason of why they buzz, possibly to do with grounding and whatnot. The solution I have heard used is to apply a small amount of nail polish to the tops, creating a barrier so that when you touch the poles, you aren't really touching the poles.

    Not real sure about the second question, but if a difference is normal, I don't think it should be excessively noticable. Could be a dodgy pot, or it could be the wrong sort of pot. A blend pot should be the type where the graduation is linear, so that the volumes roll off and on at the same rate, if its the other kind (acoustic? Whatever, non-linear) the roll off and on will not be consistent. I don't have any experience in the matter, I'm just guessing, so I could be wrong. And I don't know how to help with a solution.

    For the third, at first read I thought it may be problem relating to the ground. Not real certain any more though. I'd check your ground and shielding, thats all the advice I can offer.

    Josh D
     
  3. talked to Dimarzio, they said the pole piece is improperly grounded (just that particular one), and after messing around with the wiring I believe it.

    The grey wires ground the pole pieces, the green ground the pickups and the red are hot. They said to bring the pickup by or mail it to them, since I live in brooklyn I might just bring it by. (They are in Staten Island)

    Im still having the drop in output at the center detent of my blend knob, I tried just switching the ground and hot of one pickup to see if I accidentally wired it out or phase, but that wasn't the case. Its odd because there is a noticable drop in volume as you pan toward the center. As you pan out, its gets louder, as if I were turning a volume knob as I panned.

    I have one volume, a blend, mid boost cut, bass/treble stacked boost cut. Everything appears wired correctly except that the blend isn't grounded, and there isn't the hot running from the blend to the output like in the diagram. Could that be the problem, it doesn't seem like it would make a difference.

    Thanks for the replies.
     
  4. JP Basses

    JP Basses

    Mar 22, 2002
    Paris FRANCE
    What value is your blend pot? with single coils it should be a 250K (500K for dual coils). If you have this value correct and the bass still doesn't work properly then your blend pot is not the correct type and you need to purshase another one. In fact guitar intended blend pots are special and provide a 100% for each lead when centered.

    Peace,
    JP
     
  5. The blend is 500 k, the same as my volume, and what dimarzio recomends for the ultra jazz. Im going to write to them concerning this, or maybe I'll just call.

    I wired the bass up exactly as shown in the aguilar OBP-3 instructions, excluding one wire from the bottom prong of the blend to the stereo jack. Could that be the cause of it?

    Im going to break out the sodering iron, any responses would be appreciated.

    J.P.- thanks for the response, I didn't think it was normal for that to happen.
     
  6. Moo

    Moo Banned

    Dec 14, 2002
    Oakland, CA
    When your blend pot is in the center you have two pickups on full in parallel. That will be quieter than a single pickup. The way around this is an active preamp that actively blends the pickups. J-retro and Wal does this, many preamps don't. It's a different tone but a good one so if it really bugs you look for a preamp with an active blend.
     
  7. thanks for the reply Moo, I thought I had heard that before, but from what JP said it seemed like the signals should have been ok.

    I guess I just have to deal with the quieter signal. Thanks again