I own a SX J-Bass which I am very happy with, but there are some thinks I'd like to change. The Jack plug in my bass is too large for the cables so it doesn't always make contact (which is EXTREMELY annoying, because sometimes I play and the sound just goes off for a couple of seconds). Is there any way to replace or fix that? How much would it cost? The knobs on my bass are just cheap plastic knobs that go off all the time. I want to replace those (which I believe it's gonna cost almost nothing), but I'm not sure I'll be able to find knobs with the same in my shop, so what kind (and what style) of knobs should I get to keep as much as possible the design of the J-Bazz? I haven't played other Jazz Basses, so I can't compare, but would it be worth replacing the SX pickups? Would I notice the difference?