Overall, Zu makes a line of speakers that is amp-friendly to a wider range of electronics than any speaker brand I can think of. 101db/w/m efficiency that can also handle high power tube or solid state amps without distress. Relatively flat impedance curves, controlled floor & ceiling effects in Omen Def and Definition, check. Omen, the older Druid and Presence are/were ambidextrous about solid state or tube suitability. Superfly, the upcoming Coax and Definition "work" with anything but are considerably more exclusive about amplifier compatibility to sound musically outstanding (though this isn't strictly a cost issue, as the synergy between Quad II & II-Forty and Zu demonstrates). They are less forgiving of compromises in solid state designs than same in tube amplifiers, but overall there is a much narrower range of optimum amps for Superfly, Definition and the upcoming Coax. Still, people who don't like or don't want a tube amp have a half dozen compatible (and exceptional) solid state brands that make music with Zu. And sure, I'll put ASR among them. I think you can get much further with the right tube amplifiers but that doesn't really matter unless you're asking for direction. For whatever reason a Zu owner wants or prefers solid state amplification, they should have it. The issue here is that these forums become a permanent record of advocacy on the web.
Zu Definitions solve so many problems in music presentation that the amplifier just has to be good to put you in the realm of convincing hifi. The reason these amplifier topics become controversial is because the speaker is so good that once you hear it with even reasonable associated gear, the human brain (being a hungry beast) gets focused on extracting the nth degree of performance. And there's another thing: Zu upends the traditional weight in hifi given to the source. The amp/Zu interface becomes -- after the speaker itself -- the single most influential element in your system's sound. In a Zu system, much more rides on the amp selection than in systems built around most other speakers. Hence the heat the topic generates.
Phil
Zu Definitions solve so many problems in music presentation that the amplifier just has to be good to put you in the realm of convincing hifi. The reason these amplifier topics become controversial is because the speaker is so good that once you hear it with even reasonable associated gear, the human brain (being a hungry beast) gets focused on extracting the nth degree of performance. And there's another thing: Zu upends the traditional weight in hifi given to the source. The amp/Zu interface becomes -- after the speaker itself -- the single most influential element in your system's sound. In a Zu system, much more rides on the amp selection than in systems built around most other speakers. Hence the heat the topic generates.
Phil