Absolutely, as HD mentioned, 29 vs 27.4! That's quite noticeable, though there is something else at play if you have to turn the volume up by 5 dB. Which AVP is it? Then again you did say it wasn't by measurements, just what you perceived as the same loudness, and that is not reliable. The difference should be less than 3 dB in theory unless Emo or/and Rotel's gain spec are/is not accurate. Even then, I would say 5 dB is too much of a difference even if their specified gains were a little off. For example, may be the A300 was actually 29.5 and the Rotel 26, that still wouldn't come to 5 dB unless your perception happened to be off by a couple dB lol so many if...., just measure everything and you will get the true answer.