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"Hum" problem on MTD Heir J/MM pup setup

Discussion in 'Pickups & Electronics [BG]' started by duckbutter, Jul 13, 2005.


  1. duckbutter

    duckbutter

    Mar 30, 2005
    I have a MTD Heir 4 string, with the J/MM pup set up. Nice bass, GREAT feeling neck.
    Here’s the issue…when the MM pup is soloed and the J is off, no hum. When I start to mix in the J pup (separate vol knob) the hum begins and grows louder as the vol on the J pup goes up. When I solo the J there's a lot of hum as well.

    As a last resort, I may change the pup's, but I'd rather see if I can fix it first.
     
  2. P/ups aren't really my forté, but I would assume that MM style pickups are humbucking pickups and therefore produce less or no noise.

    The J p/up is a single coil, and is prone to at least a little noise regardless of the type or p/up or bass, and depending on the environment you're playing in. 'Tis the nature of the beast.

    There are a number of strategies for getting rid of some of the hum, which I'll let some of the more experienced guys explain (or you could probably search for).
     
  3. duckbutter

    duckbutter

    Mar 30, 2005
    I know the J pup will hum when soloed, but I kind of thought that when both pups were full on there wouldn't be any hum at all.
     
  4. Nedmundo

    Nedmundo Supporting Member

    Jan 7, 2005
    Philadelphia
    That happens on a traditional J bass, because when the volumes are equal the two single coils essentially become a parallel humbucker. At least that's how I understand it. It's like going to the "notch" hum-canceling positions on a Strat.

    But this won't work when the single coil is matched with a humbucker.

    To eliminate the hum, you might first try better shielding. If that doesn't work, maybe move to a hum-canceling J type pickup, assuming they'll fit in the MTD. Or maybe you could use a coil splitter with the humbucker, and make sure the active coil is reverse wound relative to the neck pickup. Then when the volumes are equal, it should cancel the hum just like a regular J bass, and you'll get a nice J tone too.
     
  5. duckbutter

    duckbutter

    Mar 30, 2005
    Or maybe you could use a coil splitter with the humbucker, and make sure the active coil is reverse wound relative to the neck pickup. Then when the volumes are equal, it should cancel the hum just like a regular J bass, and you'll get a nice J tone too.[/QUOTE]


    I'll try that, but this will only work if I have 4 leads from the MM pup, right ?
     
  6. Nedmundo

    Nedmundo Supporting Member

    Jan 7, 2005
    Philadelphia
    I believe that's correct.
     
  7. I cut a thin piece of sheetmetal in a rectangle to the dimentions of the bridge p/u cavity. I drilled a hole in the center, screwed it down to the body and connected the existing ground wire from the bridge P/U to the same screw by either stripping some insulation off the wire an wrapping it around the screw and tightening it down OR in my case there was a screw already there with the same wire connected to it which I thought was strange since there was no plate there.
    This helped quite a bit. If for some strange reason it is still no help then suggest you get a Noiseless Bridge J pup.
    Note: Make sure the back of the pickup does not short out on the plate or you will loose your signal. Typically there is a piece of foam under the pickup that will insulate this and it will be no problem.
     
  8. You can replace the bridge pickup with a DiMarzio J or Ultra-Jazz, as both are hum cancelling types. The internal construction is a pair of single coils, side-by-side. EA + DG, which acts as a hum cancelling device. Very effective.
     
  9. I played an Heir 5 for a few years and the Jazz pickup also hummed on that bass. MTD sold me a replacement pickup that was more noise-resistant than the original, and the cost was quite reaonable. Before installing it I shielded the control cavity with copper foil, hooked all grounds to a common connection, made sure the bridge was also well grounded and installed an Aquilar OBP-3 preamp. Without installing the new pickup, the hum problem was virtually eliminated. I don't know which of the mods did the trick, but I suspect the shielding and grounding helped quite a bit. That would be easy and cheap to try.
     
  10. Zebra

    Zebra

    Jun 26, 2005
    I'd vote that you replace the J with a stacked humbucker much rather than coil split the MM. Why should you have to compromise the MM for a problem in the J? It'd be simpler to do, too. Besides, coil tapping will only get rid of the hum for some specific settings, replacing the J will get rid of it altogeather.
    You can sheild and insolate and ground all you want, that may help but it can't get rid of it altogeather. I think you're best of replacing the J.
     
  11. duckbutter

    duckbutter

    Mar 30, 2005
    Thanks guys, gonna probably go with a Dimarzio Ultra J for the neck.