Solid State Power Amp Reviews

For some years now, I've tried to free myself from playing physical media and get all my music organized on a server. It's not that I don't enjoy handling and playing discs, but it's almost impossible to keep track of them. When my collection was only a thousand or two LPs, I felt I could remember each one individually. But now I have several times that many silver discs, and I know I can't.

I've found that some audio amplifiers have sonic signatures so subtle that they emerge only over weeks of listening; yet other amps sound so distinctive—more vivid, more transparent, more dynamic—that their signatures are immediately apparent. Can those latter qualities really be inherent in the recording, or are they colorations produced in the amplifier?

When Michael McCormick, president of Bel Canto Design, suggested that I review their Black ACI 600 integrated amplifier, I accepted without hesitation. As wonderful as my reference system may sound, its dCS digital front end alone comprises four boxes and a web of cables complex enough to send many a spider spinning. Given the choice between connecting that front end to a pair of expensive, enormous monoblocks—with their similarly expensive AC cords and equipment racks/isolation platforms—or to a single, visually elegant, 45-lb box that costs $25,000, produces 300Wpc into 8 ohms, and requires only a single power cord and shelf, I think many an audiophile, even those with lots of money, might gravitate toward the latter.

Although PS Audio's Stellar M700 monoblock power amplifier ($2998/pair) is a brand-new design from a team led by engineer Darren Myers, it draws on the company's extensive experience with class-D amplification. Sam Tellig and Kalman Rubinson reviewed PSA's HCA-2 power amp in, respectively, the October and December 2002 issues, and I reviewed their GCC-100 integrated amp in January 2006. The Stellar M700's input stage is the latest version of PS Audio's Gain Cell, which they describe as a "proprietary, fully differential, zero feedback, discrete, class-A MOSFET circuit.

Years ago, when I was young and foolish (instead of old and foolish, as now), I was hanging out with a friend at a strip-mall strip club in a small southeastern city. A youngish lady approached our table in G-string and pasties and did a tableside dance. My friend's jaw scraped the floor; I, noting her lack of enthusiasm, was unmoved. The stripper noted my impassivity and stated, with irony that at the time I somehow missed, "You're a hard man."

John Atkinson, too, is a hard man, at least when it comes to audio gear. When, in January 2014, he reviewed the Pass Laboratories XA60.5 monoblock amplifier, he concluded, "It is the best-sounding amplifier I have ever used." High praise.

There seems to be an inexhaustible supply of amplifiers; it's hard to choose which ones to review. Big-name operators are difficult to ignore, while smaller outfits often complain of neglect. In the case of a new and moderately priced introduction from Krell there's no need to find excuses: it's available, it's likely to be important judging from this company's track record, and we'd all like to see just how well it performs.

This review features the KST-100 stereo power amplifier. Initially this product was differentiated from the more expensive Krell components by having an all-black livery. However, as customers showed a preference for Krell's traditional anthracite finish, the KS series is now also available in this finish.

Have I told you about my objectivist friend—the left-brain audiophile who puts a lot of trust in measurements? He has a high natural intelligence and is an extremely experienced listener, but once he knows a component doesn't measure well, he can never again experience it impartially.

I don't want to embarrass my friend, so in this story I will call him O., for Mr. Objectivity.