I've read B(AH)G's page on this subject, but I'm still not sure. I've got a Behringer head. It's got two input jacks active and passive. According to the specs the input impedance on the active input is 220 kOhms and the impedance on the passive is 750 kOhms. I'm thinking about getting the Bass Max pickup.
): 1) The BassMax works best when matched with the K&K preamp (not much of a surprise, really): 2) Different pickups require different input impedances to get the best tone from them.