So yesterday, I thought I had melted down my my amp or the pre in my bass, but have narrowed it down to the neck pickup. What was happening was when you slap the A string, there was nothing but a pop that was essentially tapping all the headroom (for a couple seconds). Monkeyed with it tonight, and realized that somehow the pole pieces had migrated upwards from where they had been, so I was constantly banging into them. The question is, what is the best way to fix this? They are J pickups. Can I put something inside the cover to act as more of a spacer, or might it be more useful just to cover the pole pieces with something non conductive on top?