Several customers of ours have commented to us that our M-60s make the Tannoys sound the best of any amplifier they've tried. I get these comments but its rare that they tell me what the other amps are. It does appear though that if the amplifier is low distortion that the speaker benefits from having more power. When the power is clean it does not sound loud- IMO/IME that is a sign of a really good system.
