I don't think that can be the case. EMG active pickups are designed to generate relatively low magnetic field and signal strength such that they *must* have the integrated preamp to generate sufficient level for use. That choice has advantages, of course... By contrast, the HZ line generates normal signal levels which means greater magnetic field, windings etc.
WORF: It is screeching... pounding...dissonant. It is not music.
RIKER: Worf, it's better than music -- it's jazz!
--Star Trek, The Next Generation