Integrated Amp Reviews

A decade ago, many predicted that amplifiers with switching or class-D output stages would come to dominate high-end audio. In a post–Peak Oil world in which the price of energy would always continue to rise, a class-D amplifier's very high efficiency in converting AC from the wall outlet into speaker-driving power would be a killer benefit. Although a conventional push-pull class-B amplifier has a theoretical efficiency of 78.5%, which would seem usefully high, this efficiency is obtained only at the onset of clipping; the need for the output devices to carry a standing bias current reduces that efficiency considerably, typically to around 50%. Class-A amplifiers are even less efficient, with a maximum of 25%; ie, three times as much power is dissipated by the amplifier as waste heat as is used to drive the loudspeaker (see "Sam's Space" in this issue).

High-quality playback of digital audio is evolving in two opposed directions. One is where a smart wireless loudspeaker, like the KEF LSX or DALI Callisto 6 C, needs to be connected to a simple source of data. The other is where a smart amplifier takes the data from wherever it needs and sends it to a pair of dumb loudspeakers. NAD's Masters Series M32 integrated amplifier ($4848 with its optional MDC DD-BluOS module), which I reviewed in May 2018, is a great-sounding example of the latter approach.

In the spring of 2019, NAD introduced the Masters Series M10 ($2749). At first I assumed that the M10 was a stripped-down, less-powerful version of the M32, but the new amplifier offers a unique set of features.

On the cold and sunny morning of February 19, 2020, a dozen or so audio critics and writers gathered at Gilmore's Sound Advice on New York's far West Side to see some new NAD and DALI products that had been unveiled the prior month at CES. It was a friendly group, and we kibitzed over coffee before clustering in the arranged seats for presentations and auditions. I doubt any of us realized that it would be the last time for the foreseeable future that we would experience this familiar rite.

Audiophiles are oblivious to the low-end music-reproduction medium that's currently staging a comeback: the cassette tape (footnote 1). I've adopted the cassette craze in my own small way. I glory in the trusted mixtape, which I play in the stereo cassette deck of my 1990s Toyota. An automobile is a dearly cherished possession in New York City; when I cruise the outer boroughs on Sunday, I want tunes galore. So I retrieved my 1996 Aiwa cassette deck, and, attic-bound as it had been for 20 years, it was in need of repair. Via Yelp, I came across Hi-Tech Electronics, a small repair-everything-electronic shop at the east end of Canal Street, in New York's Chinatown, and a mother lode of classic audio gear and audiophile nostalgia.

"We've tried making it more powerful. When I was away on holiday, some of our people cooked up a more powerful version and presented it to me on my return. It sounded awful."

In a world of me-too products, NuForce distinguishes itself from all those other components whose names begin with i by actually using a capital I. Actually, that statement is unkind, even unfair—unlike the myriads of products designed to capitalize on the Apple iPod's current sexiness, the NuForce Icon isn't designed to be portable (although NuForce does offer an Icon Mobile). What the Icon unquestionably is is a fine little piece of audio engineering, which most of those other i components are not.