Solid State Power Amp Reviews

"Grand Integra" is the name Onkyo has given to its line of perfectionist-oriented audio products, and the M-508 is the cheaper of Onkyo's two Grand Integra power amplifiers. (The flagship model is the $4200 M-510, reviewed by Larry Greenhill in Vol.8 No.8, featuring "high current capability," and rated at 300W continuous per channel.)

The components I needed to choose for my first system were never in doubt: a turntable or record changer, an integrated amplifier, and a speaker. One of each, please, in those mono days.

Today, even in stereo, that trinity would be regarded as rather traditional—or, if you prefer, purist. Digital has exploded the range of source options and loudspeaker options. Yet amplifiers have not changed much in how and what they do.

Thirty years ago, the upstart audio company NAD revolutionized the manufacturing of consumer-electronics components by "internationalizing" the process. Instead of physically making products, NAD hired a project team in one location to design a product that was then built at a sub-contracted factory located elsewhere. The arrangement allowed NAD to go into business with relatively little capital outlay and low overhead. Other companies have since copied this ingenious business model, and, as transportation and communication have improved, doing so has become easier and more efficient. It has brought prices down and quality up—mostly in the low and middle segments of the high-end audio and video markets.

Just in case you didn't know this when you bought the Parasound HCA-3500, it says on the cover of the owner's manual: "Designed in California, USA by John Curl." Described as an "audio design legend," an appellation with which he seems quite uncomfortable, John Curl has certainly been around the audio business longer than most. He's been employed by or has consulted for some of the biggest names in consumer and professional audio—including Harman/Kardon, Ampex, and Mark Levinson—and was the designer of at least two classic products: the Mark Levinson JC-2 preamplifier and his own Vendetta">http://www.stereophile.com/phonopreamps/640">Vendetta Research phono stage, still considered by many people to be the best phono stage ever built.

In December 2023, I took the train from New York to Los Angeles to attend the Los Angeles & Orange County Audiophile Society's 30th annual Gala. I took the trip because it is both stimulating and satisfying to spend an afternoon in the company of more than 200 audiophiles and music lovers; I also wanted to see John Curl presented with the Society's fourth Innovation Award, by George and Carolyn Counnas of Zesto. John was given the award "for his groundbreaking contributions to the field of solid-state audio amplifiers, circuit innovation, mastering recorders and much more."

I first met John more than 40 years ago, at a Consumer Electronics Show in Chicago, where I was blown away by John's intuitive and innovative approach to circuit design.

The Aleph Null, or 0, represents Nelson Pass's maiden product under the Pass Laboratories banner. When he left Threshold several years ago, Pass had the luxury of starting over with a clean slate, and decided immediately that he wanted to design a single-ended MOSFET amp. The result is aptly named after Georg Cantor's first transfinite number: Aleph Null, the gateway to higher-order infinities. Just as Cantor's transfinite mathematics stretched minds with its novel conceptual view of the infinite, the Pass Aleph 0 tantalizes the imagination with a new dimension in the future of solid-state amplification: a single-ended output stage.

It was almost seven years ago that Nelson Pass, whose talks and exhibits I'd covered at many a Bay Area Burning Amp DIY event and audio show, surprised me with a loan of two Pass Laboratories' XA 160.5 class-A monoblock amplifiers. Ten months later, after I'd commented that my system had challenged the XA 160.5s in the bass department, he sent me a pair of XA200.5 monos. I connected those bigger babies to Wilson Audio Sophia 3 loudspeakers and some now-discontinued digital components with Nordost Odin 1 interconnects and speaker cables. Then came my way, toward the end of 2016, the XA200.8 monoblocks ($42,000/pair).