fishman model b input impedence

First off, you may want to post this in the DB section. In any event the Model B's input impedance is not published to my knowledge, but I would guess it is at least 1M ohm. The preamp was designed specifically for piezo pickups, as the manual states, so we can assume that Fishman provided an adequate impedance spec. Also, the B-II, Pro-EQ, and every other bass preamp Fishman has made has at least a 1M ohm impedance.

Although a bit different from the Model B, I use the old school original Pro-EQ for my dual-piezo-equipped DB. It sounds very natural and provides great tone-shaping functionality when I pair it with my GK MB112-II.

You may want to contact Fishman support on your question; they are very good about replying quickly.