I see a GREAT deal on these active Seymore Duncans (99 bucks, but will probably be less because I know the people at the store) to drop in my MIM Fender Jazz, and I was wondering if anyone had any experiance with them. Are they hum cancelling? Also, I am a bit fuzzy about this whole "active pickup" versus "active preamp" deal. From what I understand, active p-ups have the preamp built inside the pickup, and an active onboard preamp is a preamp built on the bass, right? What other differences are there? Do you still control active p-ups the same way you would control an onboard preamp? Is the sound quality any different? Is there any way to switch active pickups to passive when needed? If I leave my bass plugged in, will it drain the batteries from active pickups? Would there be enough room for a battery under my pickgaurd, or will I need to route a new place for it? What is the meaning of life? Thanks for the help guys/gals!