Need electronics help w/ excessive hum!!

Discussion in 'Guitars in General' started by mvd18969, Apr 6, 2008.

  1. mvd18969

    mvd18969 Member

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    http://i303.photobucket.com/albums/nn154/mvd18969/cx592225.jpg

    I picked up a prewired Mighty Mite pickguard to put in a Charvel Model 3 that I grabbed a few months back. From the picture, you can see it is a humbucker in the bridge w/ dual "hot rails" style single coils in mid and neck. It has a 5-way selector switch. When I got it, a friend helped me install and commented on how well made and shielded the unit was. The tone that I get from all of the pickups is awesome. Very seymour duncan-esque at a fraction of the price. The problem I am having is with the selector switch in full bridge position. there seems to be a loud hum w/ the humbucker where any of the other pickup configs are quiet as a mouse. I checked all the grounding and tried a jumper from the spring claw to the bridge w/ no success. Any ideas???? The unit is brand new and I have no idea what causing this.
     
  2. Julia343

    Julia343 Member

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    are you sure that both coils on the humbucker are "firing" properly? They should cancel out that hum. If it's behaving like a single coil that could be the problem, especially if you've got a computer running in the room.
     
  3. mvd18969

    mvd18969 Member

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    I believe so; it produces a nice fat and screaming tone that you're not going to get out of a single coil. Aside from making sure the grounds and connections are ok, I'm not sure what it could be as electronics is not an area of expertise for me. I was hoping to field any suggestions or advice if anyone on TGP has ever encountered this. It's brand new and the idea of having to take it to an electronics tech really chaps my a**; hopefully the pickup isn't defective.
     
  4. walterw

    walterw Gold Supporting Member

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    compare that humbucker to another full-size humbucker. rail-type pickups and stack-type pickups by their nature are way quieter than even regular humbuckers. maybe it's just noisy compared to the other 2 pickups.
     
  5. mvd18969

    mvd18969 Member

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    Well, I compared the pickup to another humbucker. There is definitely something wrong somewhere as the hum is extremely loud. Electronics is not my area of expertise so I am going to have to take it to someone to look at. I hate to sound stupid, but what could be wrong with the pickup to make it hum so loudly?
     
  6. Jim Collins

    Jim Collins Member

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    You say you checked all the grounds. There is probably a bare wire, or a braided shield, coming from the humbucker pickup. Is that wire soldered to ground?
     
  7. mvd18969

    mvd18969 Member

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    Well, I none of the suggestions offered seemed to lead to discovering the problem. My amp tech here in Philly also does guitar electronics work so I brought it along with me when I was taking him one of my amps for repair. As it turns out, it was wired out of phase from the factory. (hmmmmmm, I guess that stamp on the back that says passed QA means something else). Anyway he was able to get it wired correctly and now it is working perfectly.
     

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