Okay, I realize there are a hundred threads on this already but I feel as if I've read them all and still can't figure out my problem! I have a used Fender Fretless Jazz Bass MIM that I put Fender N3 Jazz Bass PUPs in. I shielded it with the Stewmac paint, put in some cavity grounds, brass cavity shielding plates, have checked and tried to establish a better ground underneath the bridge with the bare wires, have reconfigured and wired as many different ways as possible and still have a crazy hum. My P-Bass MIA 2011 does not have this problem in the same room on the same amp with the same cables. I read a thread where a guy said he got his bass dead quite with the brass cavity shielding plates from mikecd1, " Having already had this problem on my modded Jazz bass I opted to install a brass cavity ground plate I bought from darren riley (he stocks ALL Fender parts and ships same day priority). One solder connection to the cavity ground and the plate underneath the rear J pickup was installed. My bass is dead quiet and I am enjoying it for the first time. If your Jazz bass still has some hum after shielding I would suggest a brass cavity grounding plate under both pickups. You might accomplish the same thing by grounding the pole pieces with a strip of copper and a wire to the cavity ground..." Here is the link to that thread.http://www.talkbass.com/forum/f38/american-deluxe-jazz-pbass-ground-hum-noise-problem-solved-802153/ My question being (and I hate to sound electronics illiterate) but what are the "pole pieces" he is talking about? And if someone has had this problem and solved it could you post pictures? Thanks!