ok so I got a new J-Set for my Fender Jazz. It installed fine and all the soldering when well but Im getting hum. They work fine, and both volume and tone control work perfectly. The hum comes when I stand in a certain position and can go away in other positions. The control cavity is not shielded and so this might be the problem, but I thought that the EMG pickups had internal shielding anyway? Do I still need to shield the control cavity or is the hum from something else?