Bel Canto S500 Stereo Power Amplifier

Let me first state “I like this amp, I really do.” What does “Class A, A/B, D, ICEpower” mean to the average audiophile? Will there be an audible benefit by upgrading to the newer technology? If I am making an initial purchase will this technology satisfy me? Does the amp du jour really make a difference in the listening experience for the average listener?
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