Ayre Acoustics K-1 preamplifier Wes Phillips, June 2007

Wes Phillips reviewed the K-1xe in June 2007 (Vol.30 No.6):

"You guys haven't evaluated the K-1 since Paul Bolin's Follow-Up in 2002," pointed out Ayre's Charlie Hansen. "Since we supplied you with one for your MX-R review [April 2007], it might be a good time for you to update Stereophile's readers on what we've done to it over the last four years."

Four years? Most manufacturers wouldn't even have a dinosaur like that in their line any more. But Ayre's different that way. "The K-1xe is waaay better than the K-1 you reviewed 10 years ago, but anybody who bought the original can have it upgraded to the xe for $1850, which represents an upcharge of only $350."

Un-uhn, Charlie—even I know that's $1850.

"You've got to keep in mind that when we introduced the K-1x, we had to raise the price by $1500—so the 10-year-old original would need to be upgraded to that version as well. Anybody who has an x version can get the upgrade to xe for $500."

Okay, I get it—I think. But what do all of these changes entail?

"Well, it does get a little confusing—partly because there was an 'unannounced' upgrade (which Bolin alluded to in his Follow-Up) and because I tend to include improvements as we develop them, but only officially announce them when they add up to a 'real' improvement that would justify an owner's sending the component in for upgrading. Who wants to go through that every time we wrest an extra fraction of a percent improvement out of it?"

The Official Ayre Upgrade Cheat Sheet:
1996: The K-1 is launched.
2000: The K-1x quadruples the capacitance of the outboard power supply, and replaces the hardwired generic umbilical cable between preamp and power supply with detachable Cardas cable.
2001: The K-1x (an "unannounced" upgrade, sometimes called the "new Ayre") replaces the soft polyurethane feet with hard, high-density polymer, adds extra RF filtering to the power supply, and changes the grounding scheme between the PS and main chassis relative to the AC safety ground. (This was the version PB reviewed.)
2005: The K-1xe ($7000, or $8600 with phono section) adds Ayre's Dynamic Power package of proprietary technologies, which are common to all Ayre xe components. These include additional RFI filtering on the AC mains, increased peak current delivery, and better filtering of rectifier switching noise.

"You know, that last one kind of ticks me off," Hansen said. "Despite our using the fastest, quietest rectifiers available, there is a residual level of noise generated when the rectifiers turn on and off. We thought we'd done our job just finding these things, but removing that trace amount of noise yields improved resolution and a more dimensional, realistic presentation."

Compared to what? Having been away from the K-1 for a decade, my first impression on receiving the K-1xe was how chunky and mechanical it seemed compared to the current generation of sleek, electronically activated preamps—including Ayre's own K-5xe. "I know you called all the gears and belts of the volume control 'Rube Goldberg–like,'" Hansen said, "but keeping a microprocessor out of there really keeps things clean, from an RFI perspective. I guess I could come up with something better if I started from a blank sheet of paper, but..."

I waited expectantly for a minute or so before realizing that Hansen probably was mentally running through all the possibilities such a change might involve. Since he's averaged between one and four years between major upgrades to the K-1, I felt it better to end the phone call than to wait for him to finish the thought.

Sound basics: It's obvious but still worth mentioning that, when I reviewed the MX-R power amplifiers and attributed to them qualities such as speed, stereo holography, and transparency, I was saying that the components used with them had those properties, too. If I loved the MX-Rs at their best and thought they performed at the highest levels I'd experienced, then I was saying that about the K-1xe as well.

Was I captivated by the delicacy and crystalline purity of Till Fellner's recording of Book I of J.S. Bach's Das Wohltemperierte Klavier (CD, ECM New Series 1853/1854)? Heck yes—the recording's unfussiness just about always sounds good, but with the K-1xe and the MX-Rs, Fellner's supple articulation of the melodic lines seemed...well, not so much richer or brighter or more exciting, just more like itself.

Writing proper descriptions of the ways in which the K-1xe impressed me is like trying to compose Zen koans: They seem cute and witty until such time as you suddenly "get" them. "More like itself" is a ridiculous thing to say, except that the recording didn't have more bass, more zing, or more anything else, so much as more of what made it unique.

The third movement, Allegro molto vivace, of Tchaikovsky's Symphony 6, "Pathétique," with Leonard Bernstein and the New York Philharmonic (CD, Deutsche Grammophon 419 604-2), is all about mood and confusion—areas in which Bernstein reigned supreme, as did the K-1xe. Wispy motivic figures swirl in and out of focus, but softly, then more distinctly, we hear a march, which grows louder and harsher until it sounds cocky—some might even go so far as to say domineering. Did I say it was all about mood? It's also about dynamic shadings, which the K-1xe handled better than I'd ever heard from this recording.

I hadn't pulled that CD out in years—not because it sounds bad, but because it's never ranked up there with the best-sounding of my best discs. Great performance, sure; it just wasn't a sonic spectacular. But, as I pointed out in my MX-R review, the Ayre components kept me pawing through my collection for those musical goose bumps, not just the sonic ones. Yet, without sweetening or sharpening the sound of less-than-reference discs, there was a quality about them, played through the Ayre, that captivated me.

Points of contact and comparison: This quality was brought into focus (ta-dah!) when I compared the Ayre with my long-term reference preamp, the Musical Fidelity Nu-Vista. The MF is getting a tad long in the tooth, but every time I consider replacing it as my reference, I'm reminded of how much I enjoy listening to music through it.

Till Fellner's Bach certainly sounded warmer through the Nu-Vista, but it had so much more sparkle through the Ayre. You might think I'm just reporting that the Ayre had solid-state sound and the MF had tube palpability, but that wasn't it. The deeper silence of the Ayre let Fellner's notes exist clearly within and yet not of the room acoustic.

Similarly, the K-1xe was far better than the Nu-Vista at extracting the different sections of the orchestra from Tchaikovsky's Allegro molto vivace. I was far more aware of the way the swirling melodic fragments were passed from desk to desk—and I heard the march earlier, as if from a greater distance.

Then I pitted the K-1xe against one of its contemporary rivals, the $16,000 Krell Evolution 202, which I reviewed> in December 2006. The differences between the Evolution 202 and the K-1xe were very subtle. The Krell's dead-flat silence and dynamic range matched the Ayre's—or was it vice versa, as I'd reviewed the Krell first? Either way, when it comes to conveying subtle tonal, harmonic, and spatial information, the Evo 202 takes a back seat to no preamp I've heard. Neither does the Ayre K-1xe.

With the Bach, I went from one to the other, finding it pretty darn difficult to find any meaningful and consistent differences to cling to. Were the harmonic overtones a tad more forward with the Krell? Was that more accurate than the Ayre? I don't know—I wasn't present at the recording session, and both preamps rendered piano sound completely plausible.

Things were even less clear with the Tchaikovsky, but in that case it wasn't because there were no audible differences. The Krell delivered more of the sound I thought I'd remembered, which, as is the case with many DG recordings, revealed a reliance on spotlight miking. Am I saying the Ayre didn't deliver that information? No, just that I didn't focus on it as much.

Is the Krell accurate and the Ayre euphonic? No. For one thing, I'm describing differences on a level so subtle they're probably even more dependent on my preferences than usual. I guess I vote for the Krell with my head, which says that one of these preamps must be right. On the other hand, it sure was wonderful to experience Tchaikovsky's "Pathétique" through the Ayre K-1xe.

Characteristics emerge through a process of comparison within our perception: Bottom line: The Ayre K-1xe ($7000, $8600 with phono stage) is a world-class preamplifier that can stand its ground with the best I've heard. When you reach that performance level, subtle differences and features make all the difference in the world. That said, the fact that, entering its second decade of production, the K-1 is still a world-beater means it offers even greater bang for the buck. And, having heard it, I want it. Listen to one, and I suspect that you will, too.—Wes Phillips