@knight of ni
I think you're right. I didn't even realize that the pickups themselves where also active. Just had to look it up. That's fine anyways as I've decided to do this upgrade to my Tune TWB-63 instead. I know for a fact that those pickups are passive as I've already tried manually wiring them in series temporarily.
I'm planning on doing the TRB upgrade at a later date, but now I know that it'll include pickup upgrades as well.
Define "active". The II series and the Korean 100x series used the same pickups (I have that on the authority of Yamaha's US service center from back when they were still selling these; the woman verified identical SKU numbers for the pickup sets of the two basses), and the leads are red=main coil, white=phantom coil, black=ground. The pickups themselves have no power supply or onboard op-amp, and so are technically passive. You can short red to white and use the pickup as a standard two-conductor, and that's essentially what the 100x's internal trimpots do (the II series boards do something a little different, can't remember what).
However, the pickups, while technically passive, are low-output enough that on the 100x board, each individual coil gets a simple FET boost applied prior to almost anything else (one of the reasons this circuit's such a power hog, and also why it's a bit noisy; 5 op-amps, 4 FETs, and a charge pump, and that's the
simpler amp board of the two TRB levels).
So if you were planning on incorporating a passive bypass, I wouldn't use the stock pickups, but the NTMB+F module, specially with its trimmable 12dB pre-gain, is more than capable of working with the stock coils, you just twist the red and white together and use that as your pickup hot. If you just have to have a push-pull in your Bart setup, single-coil mode might be more interesting, and that's as easy as separating the red and white leads with the DPDT so that in the up position, the white leads are out of the circuit.
