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Wicked tone pot buzz......

Discussion in 'Pickups & Electronics [BG]' started by the feebler elf, Oct 30, 2005.

  1. A week ago, I replaced the stock pickups on my Fender MIM jazz with DiMarzio model J's. I wired them in per DiMarzio's instructions, red to center leg of respective pot, green to body of respective pot, and black and white soldered together. So, I plug her in, and It's got the worst hum I've ever heard....then it gets better. When I turn the tone up, I get this buzzing/humming from hell.

    Yesterday, I replaced the pots and shielded the bass. The pups are very quiet now, but the buzz from the tone pot is still there. When I touch the bridge or control plate, it goes away for the most part.

    At first I was thinking that I should reshield the bass, with all shielding grounded, and a common ground point for everything, but I had the same buzzing sound BEFORE I shielded the bass, so I'm sure the shielding is not related to the buzz.

    When I first installed the pups last week, I didn't lay a finger on the tone pot. All pots are 250K. Does this sound like a tone pot/cap value issue? Or a grounding issue? Any help would be appreciated.

    BTW - The pots are wired together as stock, and the ground from the bridge is soldered to the back of the tone pot per stock wiring.
  2. luknfur


    Jan 14, 2004

    it will get better when you cut the tone down becuase hi frequencies accentuate the hum. I would still pay particular attention to the tone in terms of connections/ground. But probably a ground issue or poor connection. You can take a meter and check all your grounds/connections. And make sure you check the bridge ground just to be sure (probes from jack ground to the bridge). If you changed pots, I assume one leg of the volume pot is grounded. Also, just becuase components are new, doesn't mean they're not defective. The one thing you don't want to do in trouble shooting is assume ANYTHING.

    If you shielded the cavity, any contact with a hot lead and the shielding will go straight to ground and poor grounds will apparently actually be enhanced by shielding according to a recent post in the Luthiers forum.

    If you're still at a loss, you can hardwire the pups directly to the jack just to see if knocks the hum out (and you may be suprised at the difference in tone as well). If it does, you know your pups, jack, and bridge ground are clear and it's in the harness somewhere. If it doesn't, you know the problems lies in the those components and pretty much that it has nothing to do with the harness and it's fine. May seem like a hassle but you can randomly stab and miss (as you already know) for a long a time with no results. You have to isolate components to find the source.

    That includes the bass itself. It's easy to go right to the module that's had recent alterations in the assumption it's the source. But you need to swap basses, amps, cables - all links in the chain before you KNOW which one has the problem. You don't want to be repairing something that's not broke.
  3. Hey, thanks for the information, and thanks for the reply!