It's already in the name: HZ = hi z = high impedance, z is impedance Passive pickups have high impedance.
I think they sound terrible. I'm not a fan or them at all. "passive" and "humbucker" aren't my favorite words when it comes to pickups. --Matthew
And I have the EMG-BTS pre amp in my bass as well. It's a great bass, I just don't like the tones I get with it. --Matthew
Actually, I just played a bass with EMG-40DCs and absolutely fell in love with the sound! I'm going to try them in my NS2000/5 and prolly leave my Q5 stock...second option is to go with an EMG 40P5 in the neck position and an EMG 40J in the bridge position...but those DCs really sound sweet!!! The EMG-HZs still sound great...I'm just looking for different sounds, cuz both of my basses have subtle tonal differences and each plays differently, I want to have lots of options without buying expensive new gear!!!
Further got this advice from a guy who knows his Spector Basses, Eduardo from Spectorbassclub on Yahoo: Anyone know anything about that pre-amp? Matthew: try hot rodding the pre-amp to 18v, you'll love the difference!
I wonder if there's any truth to the rumor that EMG-HZs are simply EMG Selects repackaged for OEM use...