Why did this work? Single-coil pickup noise cure?

[Warpeg]

I got a Nordstrand SC4 bass (w/ OBP-3 preamp and Nordstrand single coil Jazz pickups) a few weeks ago and noticed it had pickup noise problems. When I touched the pickup covers (wood/covered pole pieces) it would making a buzzing sounding. The buzzing would stop if I touched any other piece of grounded metal hardware at the same time. However, the bass was noise-free if I was not touching it.

When I emailed Nordstrand about this issue, I was instructed to "ground the pole pieces" to fix the problem. I did not know what the exact procedure was for this, so I improvised:

1. Took the pickups out of the pickup covers
2. Used shielding foil to cover the whole top of the pickup/poles and left excess foil go down one side of each pickup
3. Put the covers back over the now shielded pickups
4. Connected the excess shield foil to the grounded paint in the pickup cavity
5. Put the pickup assemblies back into the bass.

Perfect! ALL of the buzzing went away. It didn't matter if it was in passive or active mode--even with the treble turned way up.

Now, can anyone explain to me why this worked?

[JacksonsMen]

someone please do.....i need to do this to my East'd J

[Espidog]

Hi Noisevayne,
I remember your original post on this problem. Good to hear that you've got it sussed now. As to exactly why it worked, well that's pretty straightforward: you grounded the bits that needed grounding!

Sorry if that sounded facile. A better explanation of it can be found at this link:
http://www.audereaudio.com/FAQ_PUMag_Gnd.htm

[Warpeg]

The info in that link was exactly what I was looking for. Thanks! I may slightly modify my design to follow these directions perfectly.