That is interesting. I'd like to see it matched at 95db as I think that is nearer the "real" sound volume and presents peaks well in excess of what some amps will control.
But, I do concede that even at 75db I'm very surprised (and skeptical) about the test results. Again, just comparing my Denon to my separate amp, there is a quality of sound difference. Not "warm, or bright or blue or green", just a very obvious harshness on certain male vocals and horns and some guitar notes that does not occur via the separate amp.
Anyway...
Just remember he was comparing to his Denon 2805, not much of a leap when you think about it this way, but comparing it to an outboard amp, huge difference IMO.
