Dismiss Notice

Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

*sigh* More wiring problems...

Discussion in 'Pickups & Electronics [BG]' started by ElBajista, Mar 11, 2006.


  1. ElBajista

    ElBajista

    Dec 13, 2005
    Sebring, FL
    I took apart the stock electronics in my SX and started to work on modding it with Dimarzio UJs and V/B/T with a mini-toggle for Ser/Par.

    I soldered it all up, and did a pretty neat-looking job. Here the things I noticed during my test run:

    -Terrible humming unless I touch strings/bridge/controls. Am I right in thinking this is a grounding problem? I wired all of the ground wires to the output socket ground. Do I have to run a wire from the output socket ground to a screw in the side of the cavity?

    -In parallel mode: Only the bridge pickup works no matter how I turn the blend knob. Sound great, but I want my neck pickup! What might be wrong here? Still have humming, BTW.

    -In Series mode: The two pickups work perfectly as one, but I still have the terrible humming.

    Any suggestions?
     
  2. Minger

    Minger

    Mar 15, 2004
    Rochester, NY
    This is going to be a stupid question, but check how you have the polarity on the pickups. Try switching the VCC and Ground (I'm not sure if its VCC on these, but the one with the power, probably black wire or soemthing).

    This way, they'll be completely out of phase, and you noise should be gone.

    You may want someone else to confirm t his though.
     
  3. ElBajista

    ElBajista

    Dec 13, 2005
    Sebring, FL
    I don't quite understand what you are saying.

    I'm using Dimarzio Ultra Jazz pickups, with the positive wire being red and the ground is green, if that helps anything.
     
  4. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Could you post a diagram of the wiring? It sounds like something is wrong with the S/P switch.

    I assume that the SX has no shielding. The new hotter pickups could just be picking up more noise.
     
  5. ElBajista

    ElBajista

    Dec 13, 2005
    Sebring, FL
    The Schematic:

    [​IMG]

    I used a mini-toggle instead of a push-pull pot. In order to use the mini-toggle I re-wrote the schematic almost identical to that picture, only turned the switch on the bottom of the tone pot clockwise 90 degrees and put it between the tone pot and output socket. To clarify, the E and F prongs are nearer to the bottom of the picture.

    I shielded the bass as well, but I don't think that that is the problem as Ultra Jazz pickups are humcancelling anyway.
     
  6. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    If you shielded the bass, did you use cooper tape? You want to fold some of the tape over the lip of the cavity where at least one of the screws are so that the cover is makes contact with the shielding.

    If you didn't do this, you should run a wire from the shielding to the ground.

    Also, make sure none of the pots or switch contacts are touching the shielding. If any of them are even close, put a piece of electrical tape between the contacts and the shielding.

    The diagram does not show a wire from the bridge to ground. I assume you have one since the touching the strings helps.

    Does the tone control work?
     
  7. ElBajista

    ElBajista

    Dec 13, 2005
    Sebring, FL
    Check. Did this.

    I didn't think of this. I'm using pots that are bigger than the stock SX pots, so it's a bit of a tight squeeze. I already had to route some extra room for the pots. I'll check for this.

    Yes, although it isn't on the schematic, I did run a wire from the bridge to ground.

    Yep, works well.
     
  8. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Sounds good. I would check that nothing is shorting and let us know how it turns out.
     
  9. ElBajista

    ElBajista

    Dec 13, 2005
    Sebring, FL
    -Buzzing: Fixed. :D liberally used more shielding around the edge of the cavity, making sure there was a firm connection between the control plate and the foil.

    -Series mode: works perfectly, and sound incredible! Very much like a P, but with a bit of J flavor. Very nice.

    -Parallel mode: works alright, except the blasted neck pickup still won't work! I don't know if this is a fault of my soldering on the switch, blend pot, or what.

    -Tone Pot: Works alright. I'm using a ceramic .1 capacitor I got from Radio Shack. When the tone is rolled all the way down, it cuts the entire signal as would a master volume. When rolling the tone back on, it gradually gets louder. For example: With Master volume on full and the tone on 50%, if I roll the tone back on, it gets louder.

    Any help?
     
  10. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    I'm assuming the neck pickup works in series? Double, triple and quadrulple check the connection from A on the switch to ground. Heck, just check all the ground (green) wires.

    That dosen't sound right. Check that the cap isn't shorting to ground on the pot end.