Weird P Pickup Noise

[scottiwkt]

I was doing a setup on my Highway One P (w/ Fender Original '62 pickup) today and I noticed something strange. I was plugged into my computer via an IK Multimedia StealthPlug and using the input monitor to set the pickup height. I found the sweet spot on one string, noted the level on the meter while plucking and used that as a reference point to adjust the pickups so that each string had equal volume.

After I had everything adjusted, I used a metal machinist rule to measure the distance from pole to string so I could write the measurements down as a reference. When I touched the ruler to each pole piece, I hear the normal 'plink' of metal touching metal. However, when I touched the leftmost pole-piece on the bottom coil (the left or top D string pole-piece) I started hearing static. If I moved the ruler around on the pole-piece itself, I was hearing scratchy static and 60 cycle hum. This did not happen on the other pole-pieces, including the other ones on the bottom coil. I also noticed that I had to raise that particular pickup side higher than any of the other to get the correct volume match.

Is there a problem with the pickup itself? Is it possible for one pole-piece to somehow ground out on something causing the hum and static? I would have thought that I would hear the same thing on the other pole-pieces in that coil if there was a problem internal to the pickup, but they are all dead quiet. Anyone ever experience this before? Suggestions or hypotheses?

Thanks for any help...I really appreciate it!

[scottiwkt]

bump...
No takers?

[GeoffByrne]

How does it sound normally ie when you play?

If it was grounding internally, it'd probably kill that side of the pickup.

[warnergt]

I'm not sure you have a problem but here are a few questions for further investigation:

Is there something different about how you touched this top D-string pole?
For example,
Was the metal ruler contacting another pole, a string, your body?

Perhaps you touched with a part of the ruler that had better (or worse) conductivity than the part that touched the other poles.

What happens if you ground the ruler when you touch to the top D-string pole? Does the noise/hum go away? What happens when you ground it when it touches the other poles?

I'm just thinking out loud here.

[scottiwkt]

I agee that I'm not sure that I have a problem...I've just never encountered this in over 20 years of doing setup and repair work on my basses an those of friends.

To answer the first question, no, it doesn't sound any different when I play, except that this particular pole piece seems to have to be set higher than I think is normal for equal volume.

I was very careful about not touching the ruler to any ground source. When I touched a string (grounded to the bridge with bridge also being grounded to the output jack), there is no change, just a crackling static noise and a 60 cycle hum if I move the ruler around. Just for fun, I took another metal object (a screwdriver) and tried the same thing...it didn't matter if I touch the pole piece while grasping the plastic handle of the screwdriver or if I was holding onto the metal shaft.

This is just a weird one and has me stumped. I would think that the pole pieces would all be grounded, by contact with the metal pickup bobbin. It's almost like this particular one is not, for some reason. Starting to wonder if the pole piece is glued into the bobbin and not making contact because of a heavy coating of glue.

I'll have to dissect it and look some more. I'm the type that won't rest until I find out why...even if it is a trivial issue.

[BellBottomBlues]

The 60 cycle hum is because the P pickup is split for noise cancellation and to make it humbucking. With the metal ruler you're interfering with its normal magnetic function.

Just pulling everything out of my arse on that one but it could be possible