What about efficient box speakers (say 92db+)? i have heard some very good results with really nice PP tube amps on speakers of this sort. For example, I heard very nice (non-syrupy) sound on a pair of Focal speakers (94db) with the Jadis Defy 7 mkIII (with Siltech loom). Likewise, I was getting superb sound on Reference 3as with a VAC 30/30 MKIII amp PP 300B amp...not as good as that same speaker with SET but really not bad at all. We also were able to rock the house with that amp on a pair of Thiel CS3.7 speakers...something that would not have been expected but it really took control of the bottom end of that speaker (far better than a pair of Octave monos, which had 4x the power on paper). Not all PP tube amps are created equal! CAT would handle all of these speakers with ease...although if your room is not so large and/or you don't listen really loud a 30 watt SET from a few brands would simply sound better.ARC,CJ, BAT, VAC, etc. Everything driving an inefficient box speakers, as I said. ... request to play a rock song at an audio show, and these systems embarrass themselves...
Equally sad is that those who don't think the sound of underpowered tube amps driving most box speakers are syrupy . People got acclimated to this syrupy sound and have no clue of what real dynamics are... I am not even gonna talk of listening to live music, as that's not a fair comparison.. I just encourage people to listen to a SET amp driving a horn
... sad on many fronts