Like others, I mostly use an active preamp in my J’s now - the Sadowsky. But, you can get a variety of tones even on a passive J by changing the pickup balance and rolling the tone knob. A few configs I’ve used:
1) Both pups full on, tone wide open - slap and plectrum, some rock pizz
2) neck pup backed way off, bridge pup full on, and tone knob backed way down - staccato pizz; this is the classic “Jaco” setting. Great for funky articulate pizz parts
3) Neck pup backed down 30%, bridge pup full on, tone full on - harmonics!
4) Neck pup full on, Bridge pup backed of 30% - 40%, tone knob backed way off - Motown thump.
#4 effectiveness depends on the pickups being used. For single coils, I like Seymour Duncan SJB2’s.
Hope that helps.