If you have a higher impedance speakers whose impedance doesnt dip much below nominal I dont think you can beat an OTL amp. To me efficiency is not as important as impedance. In fact 5 of use recently did a shootout using 4 different amps on a pair of DeVore 0/96s and the Atma-sphere 60s crushed a very highly regarded ($ 12K) P.P. KT-88 amp, an older Mastersound 32B SET integrated and a pair of Audio Note Parallel 300B amps. Funny thing is that when we bypassed the preamp section of the Mastersound it went from last place to 2nd. We used an older CAT Ultimate preamp for all comparisons.
Why people says SE is better PP
Im new and I have more 20 years with tube amps. I prefer SEMy work in my gallery:https://photos.google.com/share/AF1QipOYq0r3yyYjkhz179q5evuYNSCotX8Bl0oG5exYcM-KRBbhIGjGYMWFBLMSx-YD...