Originally Posted by mellowgerman
At least I'm pretty sure it's unusual ...
No, it isn't!
We have written about this phenomenon one, two or three times the last 14 days ...
Dave (or others) might eyplain it much better than me ...
The magnets (=pole pieces on P PUs) are NOT grounded.
The coils are reversed wired and the magnets are revers.
You will find out that touching the magnets on one coil hum, on the other they don't ... Solving the prolem:
1.) Easy but not really solving: Change coils or wires (black white).
The other coil you normally never touch will hum.
2.) Put scotch tape or nail polish onto the magnets.
You can't diretly touch the magnets anymore - but the problem remains under the protection.
3.) Take two pieces of adhensive copper foil and solder wires to them. One "short" wire between the two foils and a long one to the cavity ...
Stick the foils under the pickups (onto the magnet - between magnets and foam). Solder the wire to GND.
Now, it doesn't matter anymore if the PU is reverse or not. The "pole pieces" / magnets are grounded and won't hum anymore. It has no influence on sound or working of the PUs!
As you shielded everything, method 3 would be the best way ...
P.S.: Same with Jazz Bass! One pickup hums, the other PU doesn't!
Normally bass players play close to bridge or neck and only touch one of the JB pickups. Put copper foil under both PUs or change HOT and GND of BOTH PUs. Then, the "normally non-touched PU will hum ...