[quote name='sellisnba' timestamp='1463735210' post='3053664']
I'm thinking about adding a jazz pickup to my p bass. I was just wondering if anyone had made this modification and what did they think?
I'd be looking also to add the extra pot to the pickguard rather than a jack added to the body.
[/quote]
Yep, done all that.
Did the sound improve? Marginally.
Was it worth the money? No.
Initially I'd replaced the weak Fender pickup with a Bartolini P which was an immense improvement. After a couple of years and coming into some cash I decided to go further. If the Barts were so good I'd I add a matching J pickup and active electrics.
Chandler guitars in Kew did the work and the fashioned a new scratch plate the lot. Very good work on their part, but. . . . the sound was different with the J but (IMO) not substantially better than what I had before.
If I could turn the clock back I'd just stay with the Bart P and not bother with the rest of the work I had done. In this case it wasn't money well spent.
My advice is to get the best set of P bass pickups you can find, then (staying passive) replace the current pots and resistor with better components and play them for a year before you change anything else.