This is my experience converting from active to passive electronics in a jazz bass. The bass: my 98 American Deluxe Jazz bass (alder/rosewood, script logo noiseless pickups & 3 band preamp). Here's the story: I had been debating replacing the stock 3 band preamp in this bass for quite some time since it did not facilitate active/passive switching and it had rather low output for an active bass . So I did some research and decided on a Nordstrand 3 band preamp (concentric vol/vol, tone control with push-pull for passive, concentric bass treble controls, and mid control w/push-pull frequency selector). Wanting to maintain the vintage cosmetic I ordered black plastic knobs directly from Nordstrand (he makes them in house by modifying All Parts knobs) since I don't like metal knobs on jazz basses. On a whim I also ordered a set of Fralin hum canceling jazz pickups to complete the overhaul. So I installed the preamp and the pickups with relative ease. The Nordstrand is pre-wired for the most part but it does require extending the ground wire from the preamp circuitboard to the battery compartment for everything to fit properly. With everything installed I plug the bass into my B-15R for some tests. First impression: what a great preamp. Very uncolored when compared to passive mode and the adjustable 10db of preamp output gain on the circuit board is something all preamps should have IMO. I gave all the eq bands a quick workout and they are well chosen and very musical. The treble cut and passive tone control work well together although I wish the tone control went a bit darker (perhaps using a vintage spec .1uf capacitor instead of the .047uf). All in all, I thought I was in heaven until...I put all the knobs on. And then it hit me, literally: the concentric vol/vol pot is really tall, easy to bump and looked rather obtrusive. So I did some measurements. A stock full size volume knob is .60" tall. The concentric knob stack is 1" tall. As a point of comparison I also measured the stock Fender concentric knobs at .75" tall. It doesn't look like much of a difference when you compare them on a flat surface, but for me it was just enough to get in the way and really annoy me (please bear in mind I am easily annoyed) to the point that I couldn't continue to play it this way. I liked the way the original knobs looked better but sadly Fender used a concentric pot with smaller shaft diameters and then made custom knobs to fit. They also use a 100k pot for the bass/treble controls where Nordstrand and most preamp manufacturers use 50k or even 25k so cannibalizing the original preamp would not work either. At this point I was getting frustrated because it sounded good but looked and felt awkward. So I vowed to hunt down some shorter concentric pots if it was the last thing I did. In the meantime I decided to wire up a simple passive harness so I could at least dig into the Fralins. I used 250k audio taper pots and a .1 Hovland paper-in-oil cap wired vol/vol/tone with Evidence Audio Monorail cable. The results: pure awesome! The sound is big, punchy and responsive in a way that makes me grin like an idiot. The tone control is absolutely brilliant and virtually the entire travel of the pot is useful. This was never a bad sounding bass, but now it's a great sounding bass. The moral(s) of the story: Fralin pickups are pure delicious goodness; Nordstrand preamp sounds great, just be sure you plan the installation carefully and take into consideration the size & placement of the controls; a good .1uf tone cap works wonders. Sorry for the long thread. Passive sounds massive!