I picked up a new-to-me Jazz bass the other day, but the output is very noisy, just about regardless of the position of the cable. The only thing that makes it stop is pushing in the cable (it will move in a few more mm's from the "plugged in" position), but that isn't practical. Replace? Clean (with what)? Not the jack at all? Thanks! I know this is asked a lot, but I'm having a hard time with the search.