Russ, glad to hear how much you're enjoying the music through your M80s. Yes, very accurate speakers such as the Axioms reveal the blemishes in some recordings as well as the beauty in well-recorded discs. I've tried to suggest here(e.g., in the "Stunning Recordings" thread)great music, well-performed, that sounds terrific on my Axioms.
Incidentally, no need for "disbelief" as to how well the AG-680 drives the M80s. They're average to slightly above average in sensitivity and don't have any special amplification needs. Assuming that the AG-680 is still in good operating condition, its 100 watt per channel rating is plenty for providing safe(to your hearing) sound levels. Newer units with more up-to-date features are available, of course, but simply from the standpoint of transparent amplification, what you have is fine.
