I think we'll all live long enough to see the day when Class D is the only amp used in subwoofs. The little 350-watt plate amps in my Tylers allow for a higher-frequency roll-off that spares the tubes some real heavy-lifting and allows them to concentrate on critical mid-bass, mids and highs where (don't want to start a flame-throwing contest here) tubes still reign supreme. I also have one of those little cigarette-pack-sized 20 WPC Class D Lepais (which always seem to be on close-out for $20 from Parts Express ) that is on 24/7 hooked up to a pair of small $60 Dayton speaks for the TV: net result being an $80 "sound bar" that sounds pretty good and beats anything from Wal-Mart for $<200. (I mean, who wants to waste tubes listening to Judy Woodruff or some ancient B&W movie with a crappy sound-track anyway?)
Subject for another thread, perhaps, but why do the makers of of $2,000 flat-screen TVs include sound that is worst than a 1950s transistor radio?
Class D amps seem to be very much more speaker impedance sensitive than traditional A/B types. Knowing that an 8-ohm (nominal) speaker can wander down to 2 ohms depending on the music, I wonder about the effect on Class Ds at high levels with fussy electrostats, for example.
So much in future will depend on execution just as it does now: pwr supplies, the outputs' electrical behaviours, good ol' quality control, the quirkiness of the specific technology and the like. I can just see a snobbery develop amongst transistor types towards Class D amps the way some of my tube-loving brethren hold against s/s/ amps. The ultimate arbiter will be the ear, and we each have a different pair ...
