Okay, I did some reading in the pickup subforum (too bad reading the Bartolini site doesn't do the trick). It appears that there are two versions of the NTMB, one with push/pull volume for active/passive and one without (for active pickups).
So, my next question, what would be a basis of selecting passive mode where you have both?
Kevin pretty much always uses the NTMB with switchable mids (two bands with a push/pull pot or three with a toggle) and active /passive on the volume control.
A couple of reasons to run it passive, first as a bypass if you have a drained battery. In that mode only volume and panpot function. The second is because you like the tone with everything passive. It's definitely not simply a limp home mode... I have a couple of basses I use in passive mode becuase it sounds so good plus it matches up better with some amps that don't like as big a signal as the Brubaker can put out.
One of the things I enjoy doing when I let people check out my basses is hand it to them set passive. Mine sound great in passive mode and when you kick it into active it floors people. It's the same tone just BIGGER and tweakable. People don't associate the aggressive tone I can get with a passive bass. It's understandable.
A fun setting on just about any Brubaker, US or Brute with the NTMB is soloing the bridge pickup (JJX or MJX), pull up the mid control (that usually selects the lower 250hz range) and bump it a little and maybe bump the bass a tad. Play hard close to the bridge and get a pretty ridiculous uber Jaco-esque vibe. Great for fusion or mimicing a synth.
For such a simple setup (4 knobs with one stacked and one, two or no toggles) it's very versatile. Experimenting with it is fun and don't be afraid to max any of the controls, the electronics stay clean even maxed... just watch your amp volume when you do, some settings hit particularly hard.
On the toggles here's how they're typically wired: if you have push/pull mids there's no toggle for that. If you have non-single coil pickups you have a toggle to split the coils on the US basses. So...
no toggles is usually push/pull mids with single coils.
One toggle could either be 3 way mids with single coils or coil splitter with dual/quad coils (humbuckers) coils and push/pull mids.
Two toggles is coil splitter and 3 way mids with humbuckers.
Once you get used to the setup it's pretty easy to tweak consistently. Repeatability is probably my favorite thing about the setup, after having other basses with parametric EQ that force you to chase tone from day to day if anything's tweaked.
Kevin does a similar setup with the Aguilar OBP-3 preamp.