Most amplifiers and receivers generate a lot of heat, and in the summertime, who needs that? Worse yet, the heat they generate is "wasted" energy, meaning it's the energy not being used to drive speakers and make sound. In fact, the majority of the AC power most amps consume is turned into heat. Green, they are not! For this blog I checked out two cool-running amps: Bel Canto's REF500S ($2,495) for my audiophile readers, and the Dayton DTA-100 ($100) amp for everybody else.
Class D amplifiers are different by design, and significantly more efficient, so they run a lot cooler than conventional Class AB amplifier designs. Class D amps are available in every price range, from under $50 all the way up to high-end, megabuck extravaganzas. Class-D-powered receivers are also available, and while they're frequently referred to as digital amplifiers, Class D amps are controlled by either analog or digital circuits.
But Class D is no panacea; most of the Class D amps I've heard sound bland; they're not awful, just boring. However, the best ones can be pretty amazing.
The Bel Canto e.One Series REF500S Dual Mono (stereo) amplifier is definitely in the latter category. For such a little thing (8.5 by 3.5 by 12 inches), the REF500S is seriously powerful, it can deliver 250 watts into 8 ohm speakers; 500 watts into 4-ohm-rated speakers. Bel Canto doesn't specifically refer to the REF500S as a Class D amp, but its low-heat, ultraefficient, heavily regulated switch-mode power supply and switching output stage use a minimum of AC power.
The REF500S sounds stellar on my Magnepan MG 3.6/R speakers, which is one of the toughest speakers to drive well. … Read more