I have a Nordstrand 2-band pre (cut/boost) in my Nordy bass -- Nordstrand pickups, of course. Passive tone control also. We all know that many onboard preamps sound very active, often with a volume boost as well -- not that that's a bad thing, some love it, but the Nordstrand preamp is surprisingly natural: just a bit more hi-fi than passive, and almost no volume boost.
My favorite active setup in general is two-band boost-only plus passive tone. My Elfin Plus has an Aguilar OBP-1 plus passive tone (and Nordstrand pickups) -- the Aggie is fairly neutral as well.
I recently read that placing a passive tone after an active preamp brings output impedance closer to passive, so cable capacitance comes back into play, reducing the amount of high treble that reaches the amp. Techies, please correct me if I'm inaccurate (or wrong!) but if true, it's another reason I prefer my actives to have a passive tone.
I have to add: boosting treble with the active control and then cutting with the passive is NOT redundant! Results vary from preamp to preamp (and the value of the passive tone capacitor as well I'm sure), but typically you get increased presence (hi mid, lo treble) without all that high treble info you get from active treble boost alone.