Used to drive my 88dB Sonus Faber GM's with 75w of KT88's in a 14x17 room with no problem. Plenty of dynamic punch and no soundstage shrinking or congestion.
My Tannoy Kensigton are 93dB and 10w is plenty in my 14x21 room unless I really want to crank it which I usually never do. 96dB peaks are totally realistic though but at the cusp of where the Cortese starts to lose it's grip.
Jerome, besides efficiency, impedance swings are very important and if the load the tube amp down, it doesn't help if they are more efficient. Most tube friendly speakers are 8 ohm and more importantly, STABLE when it comes to impedance.
When I tried the MC2102 with 100w, there was absolutely nothing to gain in my system. Moreover, the 2102 sounded too warm and lacking luster with my Tannoy's. Blah.... too boring!
On the same note, the Ayon Crossfire of 30w SET power sounded absolutely sparkling and dynamically alive in my system. With the same efficiency Verity Audio Eleonore, it was a different story. It sounded like it was running out of juice and was congested and thick/muddy sounding. More drivers, more complex crossover, you see, results will vary.
Shindo owners all seem to have knowledge of few speakers out there that work well.
I dont blame Matt for not feeling comfortable with that recommendation. His honesty is most appreciated too!
Jerome, the question is, are you prepared to change speakers if need be to get the Shindo amps to really sing?