I did not connect the J QP’s to the matching SD STC preamp, since my goal was to install Apollo’s and the preamp went in later. There was a stock SD-designed preamp (lower tier) in the bass that the QP’s seemed to be overpowering. I’m sure the higher spec STC preamp would’ve better handled the QP’s. I wonder what’s possible for the QP’s with a well-designed passive circuit and/or something like the buffered EMG ABC blend. If I had an extra J bass lying around that needed pickups, we’d find out…