Audacious Audio

I well remember my first "real" headphones: a pair of Koss Pro4AAs that I bought back in 1970. The Kosses were relatively expensive, but, like headphones today, they allowed an audiophile with limited cash to get a taste of high-end sound that was not possible with a speaker-based system. I bought the Pro4AAs because I had become fascinated with how the images of the instruments and singers were strung along a line between my ears inside my head. It seemed so much more intimate—a more direct connection with the music—than playback through loudspeakers.

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.

With the help of 20:20 hindsight, it looks as if I made a decision when I joined Stereophile: to review a loudspeaker from Wilson Audio Specialties every 11 years. In June 1991, I reported on Wilson's WATT 3/Puppy 2 combination, which cost $12,740/pair in an automotive gloss-paint finish. This was followed in July 2002 by my review of the Wilson Sophia ($11,700/pair). And now, in December 2013, I am writing about the Wilson Alexia, which costs a not-inconsiderable $48,500/pair.

Even as the gulf narrows between the sounds of the best solid-state and the best tubed amplifiers, most listeners remain staunch members of one or the other camp. Similarly, when it comes to video displays, the plasma and liquid-crystal technologies each has its partisans, though that conflict's intensity is relatively mild, perhaps because video performance, unlike audio, is based on a mastering standard that establishes color temperature, gray-scale tracking, color points, and the like (I'm deeply in the plasma camp). But in audio, the "standard" is whatever monitoring loudspeaker and sonic balance the mastering engineer prefers, which makes somewhat questionable the pursuit of "sonic accuracy." Still, in a power amplifier, a relative lack of coloration is preferable to amps that Stereophile editor John Atkinson has characterized as "tone controls"—usually, if not exclusively, of the tubed variety.

I had been anticipating getting to audition a pair of TAD loudspeakers in my system since the introduction of the original TAD Model-1, in 2003. It was designed by Andrew Jones, who had recently assumed the mantle of chief designer at Technical Audio Devices Laboratories (TAD), at that time a subsidiary of Pioneer. Although TAD dates back to the mid-1970s, its research and development efforts had been focused on the professional sound market, something that continues. Jones came from a long line of speaker innovators at KEF and was assigned the goal of developing state-of-the-art speakers for the domestic market.

In the September 2005 issue (Vol.28 No.9), I reviewed Simaudio's first reference-quality power amplifier: the 1000W, 220-lb Moon Rock monoblock ($37,000/pair). At the time, the Rock was a dramatic departure for Simaudio, then primarily known as a maker of midpriced gear that was good for the money. I found a lot to like about the Rock, concluding that while it wasn't quite up to the standard of the best superamps of the time, it was very good—and, for Simaudio, an admirable first shot at the state of the art.