I have been playing bass for many years and have owned both passive and active basses. For the last ten years I have been playing the same jazz bass and have not played anything else other than trying something at a music store. I want to put some more oomph into my bass. I have never played a jazz with active electronics...well, maybe emgs back in the day. Currently, the pickups in the jazz are stock as are the electronics. My questions concern the addition of the preamp. Is it worth adding a preamp to the existing pickups, or should they be upgraded as well? Does it matter if the pickups are humbucking or single coil? I have pretty much decided that I want to make the preamp an onboard one. Not sure what company to go with yet, but I want to sort out the questions concerning the original pickups. Thank you for your help.