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P Bass wiring issue.... Maybe?

PotsdamBass8

PotsdamBass8

Supporting Member
Jan 23, 2005
2,991
3,023
Long Island, NY
#1
So I just got a honeyburst fender American special from GC's used site ImageUploadedByTalkBass1377131287.285869.jpg, and while its in great shape, when I plugged in in my garage, it hums like a single coil. I even tested it against my yamaha bb424x, and when it's in single coil only mode, it hums exactly the same. When I use just the p pickup on the yamaha, dead silent. Now I took the pickguard off to try to see if there was anything obvious, but I can't really tell. I'm not that up on my wiring. It does look like some wires were poking out of the pickguard a little and there was scratching at the edge by the finish like someone tried to push them back under. That would imply that someone might have take it apart at some point. I also don't really see the claimed "greasebucket" wiring. Is there anyone here with knowledge of these things that can tell me if there's anything obviously wrong with the wiring?

Thanks!
 
#3
Checked the bridge ground wire, it was touching. It's so weird because it behaves and sounds exactly like my pj bass with both pickups or just the j.

Is it possible to wire a p pickup so it doesn't cancel hum? I know when you have two jazz pickups then they have to have reverse polarity to hum cancel when they're both on equally, is it possible that the two halves of the p were not reverse polarity from the factory?
 
#5
Your bass gets a hum, does it go away when you touch the metal/strings/bridge? If so, then you have a shielding issue, Fender does nothing in terms of shielding jobs pre-2008. Their shielding job post 2008 is a joke anyways, so it does nothing.

I bet that bass is dead silent once you give it a proper shielding job.
 
#6
OK, here's the deal: check the polarity alignment of the magnet polepieces in each of the two pickup segments. They should be opposite, for the RWRP wiring that makes a split-P-pickup humbucking. If they are the same, then somebody made a mistake and got two of the same half, and then it's just like any other dual-single coil in series: hum and more hum. If they are different, then you could still get hum if the wires connecting one segment to the other are reversed. If this is the case, try flipping the leads of one half of the pickup as to which wire goes to te other half and which lead comes out to the controls.
 
#7
iiipopes said:
OK, here's the deal: check the polarity alignment of the magnet polepieces in each of the two pickup segments. They should be opposite, for the RWRP wiring that makes a split-P-pickup humbucking. If they are the same, then somebody made a mistake and got two of the same half, and then it's just like any other dual-single coil in series: hum and more hum. If they are different, then you could still get hum if the wires connecting one segment to the other are reversed. If this is the case, try flipping the leads of one half of the pickup as to which wire goes to te other half and which lead comes out to the controls.
Click to expand...

Thanks, I will check this.

The hum does not go away when I tough strings or other metal.
 
#8
Angel LaHash said:
looks ok to me
Just make sure that Ground on the Volume isnt touching the output to the jack
also what size cap is that!
Click to expand...

There are wires connecting the ground lug, volume pot, tone pot, output, and bridge ground all in one line. Should that not be the case?

Also no idea about the cap, I was just expecting it to look different since it supposedly was the greasebucket tone control.
 
#9
If you have it wired correctly as shown in Rob's link and the buzz is constant you have a more serious issue. Have you removed the bridge and check the ground connection under there? I improve that connection with a slip of copper foil tape under the bridge.
 
#10
iiipopes said:
OK, here's the deal: check the polarity alignment of the magnet polepieces in each of the two pickup segments. They should be opposite, for the RWRP wiring that makes a split-P-pickup humbucking. If they are the same, then somebody made a mistake and got two of the same half, and then it's just like any other dual-single coil in series: hum and more hum. If they are different, then you could still get hum if the wires connecting one segment to the other are reversed. If this is the case, try flipping the leads of one half of the pickup as to which wire goes to te other half and which lead comes out to the controls.
Click to expand...

Update: finally got around to borrowing a soldering iron and swapped the wires coming from one half of the pickups - dead silent now. Thanks for the help!
 

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