I first met electronics engineer John Dawson in 1979, at a British audio show. The company he'd co-founded, A&R Cambridge, had just launched the A60, a slim, elegant-looking, 40Wpc integrated amplifier costing only £99 (then equivalent to $217).
By the time I reviewed the Mk.2 version, in the October 1984 issue of Hi-Fi News & Record Review, the A60's price had risen to £199 ($248), the company was now called Arcam, and more than 22,000 A60s had been sold, making it one of the best-selling amplifiers in England. While preparing that review I had visited Arcam's factory, near the English town of Ely, where Dawson had shown me filing cabinets containing a separate manufacturing report for each and every one of those A60s.
Class-A amplifiers have a well-deserved reputation for being power guzzlers that run hot enough to burn fingers. They're inherently inefficient because their output devices conduct full current at all times, and much of that current is dissipated as heatrequiring, in the case of class-A solid-state amplifiers, massive heatsinks. This is why class-A amps tend to produce relatively low power, and tend to be heavy and expensive to buy and run. And these days, energy inefficiency is out of fashion.
Imagine if you can a power amplifier with the bass richness, midrange liquidity, and high-end accuracy of the best tube amplifiers, and the inner detail, transient attack, and bass solidity and range of the best solid-state amplifiers. If you can imagine that, you can visualize what this amplifier sounds like.
In the May 2015 issue, I fairly raved about Simaudio's Moon Evolution 740P line-stage preamplifier, and now here I am confronting its Moon Evolution 860A power amp. The two are companion models of sorts, with prices of $9500 for the 740P, $15,000 for the 860Aand for much of the time I spent listening to the 740P it was hooked up to the 860A, so some of the descriptions of sound in this review will seem familiar. The two components are both products of the same design shopSimaudio, Ltd., of Quebec, which has been a prominent brand in high-end audio for 35 yearsand are often marketed as a pair, so it should be no surprise if they have a common sound.
Of the hundreds of product reviews I have written over the years, it is perhaps those of power amplifiers that present the hardest task in defining their worth. This is not because power amps are unimportant. As I wrote in my review of the MBL Corona C15 monoblock, in June 2014, "it is the power amplifier that is responsible for determining the character of the system's sound, because it is the amplifier that must directly interface with the loudspeakers. The relationship between amplifier and loudspeaker is complex, and the nature of that relationship literally sets the tone of the sound quality." But because the amplifier's role is so fundamental, it can at first be difficult to determine a given amp's balance of virtues and failings. A paradox.
Stereophile normally doesn't review audio systems. We review individual components. We've made an exception for the Bel Canto Black system because it deserves to be evaluated as such. It consists of three dense, almost identically sized cases of black-anodized aluminum. One, the ASC1 Asynchronous Stream Controller, is what in a conventional system would be called a "preamplifier." The other two, a pair of MPS1 Mono PowerStreams, would in a conventional system be called "monoblock power amplifiers."
We cannot recall when any new products have generated as much of a stir among perfectionists as the new solid-state equipment from Audio Research. Preceded by rumors of "a new kind of amplifying devicea cross between a tube and a transistor"the announcement of ARC's new power amp and SP-4 preamplifier elicited very mixed reactions from loyal ARC customers, some of whom gleefully anticipated a virtual revolution in audio electronics, others of whom felt betrayed by the company which, having originally convinced them that "Tubes Are Better," suddenly seemed to be doing an about-face and espousing the views of the Enemythe "Soiled-State"forces.
Google Bricasti and all that comes up are sites relating to Bricasti Design products. The name must be fancifulit sounds Italian, but cofounders Brian Zolner and Casey Dowdell most likely are not, and the company's headquarters are not in Milan or Turin but in Massachusetts.
While its name might be whimsical, nothing else about Bricasti is. As John Marks reported in his review of Bricasti's M1 DAC in the August 2011 issue, both founders previously worked at Lexicon: Dowdell as a DSP-software engineer, Zolner as international sales manager. Bricasti develops its products in conjunction with Aeyee Labs, formed by a group of ex-employees of Madrigal Audio Laboratories and based in New Haven, Connecticut.
Several seconds after I began listening to it, I knew that Theta Digital's Prometheus monoblock amplifier ($12,000/pair) was different from other amplifiers. The violins and brass were more dynamic, and had more pace. The orchestra sounded more three-dimensional, depicted in relief by a degree of hall ambience I hadn't heard when I played the same recording through my reference solid-state stereo amplifier, a Mark Levinson No.334.
Power amplifiers are unglamorous but essential. In theory, they have only one task. But, according to audio sage Yogi Berra, "in theory, theory and practice are the same. In practice, they are not." Amplifiers must take a voltage input signal and provide an output of somewhat higher voltage but of substantially higher current, the product of which is power. The task is complex in that this output must be applied to electrical interfaces whose characteristics vary widely from speaker to speakeracross the audioband and, for some, even at different power levels. There are no control mechanisms or feedback signals to help. The power amp must just stand and deliver.
A year or so ago, in my review of the Pass Labs XP-30 preamplifier, I wrote that the heart of an audio system is the preamplifier, in that it sets the overall quality of the system's sound. But it is the power amplifier that is responsible for determining the character of the system's sound, because it is the amplifier that must directly interface with the loudspeakers. The relationship between amplifier and loudspeaker is complex, and the nature of that relationship literally sets the tone of the sound quality.
Very few products exude opulence as do the Rowland amplifiers: the massive chassis, the gold finish, those sculpted handles on the front plate. For some strange reason the amp reminds me of Brutus Beefcake, the golden boy of professional wrestling, upon whom I stumbled one night while flipping through the myriad channels of our cable TV. The visual impact is the same: beefy. And then there's the price: also beefy.
Whereas the Pass Labs preamplifiers are designed by Wayne Colburn, the power amplifiers are the work of company founder and high-end audio veteran Nelson Pass, who even lays out his own circuit boards. The X-model amplifiers, beginning with the X1000 in 1998, were the first implementation of Nelson Pass's patented Supersymmetry topology (see "Nelson Pass on the Patents of Pass"). The XA series, which debuted in 2002, combined Supersymmetry with the single-ended class-A operation of the Aleph series. The XA.5 models offer detail improvements over the XAs.
Lindell Audio, a Swedish professional-audio company, was founded in 2010 by recording engineer Tobias Lindell, and claims to offer equipment "by engineers, for engineers." Tobias Lindell specifies the features and functions that he wants each product to incorporate; the actual circuit designs are by others. Although Lindell's corporate headquarters are in Sweden, the products are manufactured in China, and are competitively priced.