Ayre KX-R TwentyReviewers' ChoiceColor me skeptical. This review is a month late because I was having a hard time accepting the announcement of Ayre Acoustics’ new KX-R Twenty preamp -- and, subsequently, requesting to review it. The original KX-R had been my reference for some two-and-a-half years -- longer than I can remember any component staying in my system since I began this reviewing thing back in 1998. Sure, other preamps came in for review. But then they left. I can’t say I was ever tempted to replace the KX-R, not even with substantially more expensive components that I was able to compare it with, side by side. The KX-R was the quietest, smoothest, most resolving, most enjoyable preamp I’d had in my system. Heck, it might be the single best stereo component I’ve ever owned.

Then I heard from Charles Hansen, Ayre’s founder and chief designer. When I told him I was having difficulty imagining an improvement over the KX-R, he said, “I was having a hard time imagining it also. I really felt like the KX-R was probably our best product ever.”

I wanted to talk him out of the upgrade: If it was that good, why change it? Then, as Hansen continued, the reasons began to make sense.

“The problem is that there is only one surface-mount resistor I have ever heard that sounded any good at all, and that is what we used in the KX-R. The original price was 90¢ each, and we needed over 70 different values to make the volume control. The smallest reel size was 1000 pieces, so we had to make a $60,000 investment just in the resistors just to put it into production. Then we got some bad news last fall. They had to increase the price of the resistors -- to $2.80 each! This more than tripled the cost of the resistors -- and there are over 400 in each unit. That is why one KX-R costs as much as two MX-Rs.

“But now we were in a huge pickle. We had to raise the price of the unit over $4000 to pay for the increase in the resistor prices. Plus, to buy enough resistors to make another run would cost us nearly $200,000! Cough, sputter. The only solution was to figure out a way to make it sound significantly better. The problem was that I had several ideas on how to improve the MX-Rs, but absolutely no idea how to improve the KX-R. For nearly a year, I had the sword of Damocles hanging over my head.

Ayre KX-R

“Then, when we came out with the AX-5 [integrated amplifier, which] had the Diamond output stage, I knew that we had a possibility, at least. The Diamond output stage made a much larger improvement than I was expecting. So I figured that we would try it on the KX-R. It worked so well that I took it to an extreme. And the KX-R got even better. By the time we were done, I literally could not believe what I was hearing.”

So, of course, my interest was piqued -- particularly since I now understood the reasoning behind the nine-grand price uptick. But what exactly does the upgrade entail? I asked Hansen to detail the nuts and bolts.

Ayre KX-R

“We rebuild the gain adjust (volume) switches, we completely replace the logic PCB so that the motor noise is reduced. (No more thunk, thunk, thunk when changing volume levels -- now it goes zook, zook, zook, and is less than half as loud.) We replace the complete audio circuit and power-supply regulators. The only things that are retained besides the chassis, knobs, and transformer are the connectors and the connector PCBs. So you really are getting a new product for $9000 -- the price difference between the old version and the new version. It literally is a new design in the same chassis.”

The review was on.


The KX-R Twenty (17.25"W x 3.75"H x 11.5"D, 40 pounds) looks basically identical to the original KX-R, which Peter Roth reviewed in December 2010. The only outer differences are the “Twenty” badge on the right side of the chassis, and a slightly modified "Ayre" badge on the left side to make it more resistant to peeling off. There are still eight inputs, including four balanced (XLR) and four single-ended (RCA), with two pairs of balanced (XLR) outputs and two balanced (XLR) tape outputs. The Variable Gain Transconductance (VGT) volume control works the same, with 60 increments of 1dB. The rotary controls for volume and source selection remain unchanged, as does the backlit remote. Operationally, the KX-R and KX-R Twenty are identical, so everything Pete said about that in his review applies here. The KX-R cost $18,500 USD when it was available; the KX-R Twenty costs $27,500. You can update a KX-R to Twenty status for $9000, for which Ayre will provide a new five-year warranty. I’m told there is no difference between an upgraded and a new KX-R Twenty; Ayre takes care of its customers.


The KX-R Twenty was installed in a system consisting of Ayre MX-R mono power amplifiers driving Magico S1 or Q7 loudspeakers, all connected with Siltech Explorer (S1) or Nordost Valhalla (Q7) cables. Source components were either the Aurender X100L music server or my trusty MacBook. DACs included the Resonessence Labs Invicta Mirus or the M2Tech Young DSD. Having used the original KX-R for so long, as well as with all of the components just mentioned, I had a solid basis for comparing the old and new models. I had no operational problems with the KX-R Twenty -- it performed flawlessly throughout the review period.


Describing the sound of music through a high-resolution audio system can be a funny business. I’ve often wondered what accounts for such varied impressions of a single component when it’s listened to by multiple audiophiles: one man’s detailed is another’s bright; one listener’s properly full bass sounds, to another, bloated and inaccurate. And so on. Certainly, ancillary components and room acoustics greatly contribute to these differences of opinion, not to mention the recordings themselves, and how they were made and engineered.

But still . . .

Even with all of the varied opinions out there, I don’t hear many complaints about the sound of Ayre Acoustics products. Almost everyone who hears Ayre gear finds it hard to criticize. The Ayre sound might not be as bold and upfront as some other companies', or have the whomping bass preferred by certain listeners, but it always seems to be smooth, revealing, and just plain easy to listen to over the long term. That was certainly true of the original KX-R.

Ayre KX-R

Yet those are exactly the qualities that the Ayre KX-R Twenty improved on. Yes, I know -- that might be tough to swallow, especially for those of you not lucky enough to have heard a Twenty in your systems. But in my system, the Twenty upped the ante on everything that was special about the KX-R. That’s what makes it so doggone special.

I’ll start with Ayre’s signature smoothness. When I began listening critically, after having broken in the KX-R Twenty for a number of weeks, it wasn’t long before I heard improvements. For me, it all began with voices. I first listened to some old standbys, such as Margo Timmins’s haunting vocal in the Cowboy Junkies’ The Trinity Session (16-bit/44.1kHz AIFF, RCA 88568). Although my intention had been to try only a track or two, the sound was so darn mesmerizing that I listened to the entire album. If you define smoothness as a combination of grainlessness and utter neutrality of tone, then the KX-R Twenty was basically perfect. It was easy to hear deep into Timmins’s voice, but there was no electronic sizzle accompanying the detailed yet nonaggressive sound. If you listen to this preamp side by side with your own, you may be surprised at how much electronic noise your system has been producing.

Ayre KX-R

Listening to these vocals revealed other things. For starters, there was the absolutely free-flowing nature of Timmins’s voice. Beginning with “Mining for Gold,” the track that most everyone who listens to this album uses as a reference: The sound was absolutely spooky -- music poured from my system so liquidly that it made the sound of the original KX-R seem downright shackled by comparison. Timmins’s voice hung tangibly in space, so clearly delineated that it sounded as if the system was being fed a live microphone feed. What really impressed me was that the sound was in no way forced -- the voice just appeared, in palpable yet easygoing fashion. I’ve heard listeners ascribe this type of sound to components whose circuits use no overall negative feedback. In fact, this characteristic seems to be a trademark of the house sound that has made Ayre gear so popular among audiophiles. Now, this sense of flow was enhanced. The cohesive, liquid sound I was hearing with the KX-R Twenty at the helm added to my enjoyment because it was so un-hi-fi; again, the strengths that had made the original KX-R so good were even stronger in the Twenty. It was the least fatiguing sound I’ve heard from my system.

The KX-R Twenty’s liquid, utterly smooth sound in no way obscured the fine details that captivate listeners and can greatly add to that ability to, for a moment, suspend the disbelief that you’re hearing live musicians performing in your room. The crystalline clarity that I heard listening to an old standby -- pipe-organist Mary Preston’s Crown Imperial, with Jerry Junkin and the Dallas Wind Symphony (24/176.4 WAV, Reference HRx-112) -- was awe-inspiring. The decay of the notes from the percussion was subtle but tangibly present, and made the recording sound spacious without any artifice. The organ was powerful down low, and instruments were kept more distinct and recognizable than I’d ever heard through my system.

Ayre KX-R

The KX-R Twenty was able to pull it off by combining standard-setting smoothness and high resolution with an ease of sound that is uncommon, to say the least. Let’s face it -- there are times when high resolution can sound spotlit at certain frequencies and therefore is not easy to relax to; more frequently, a system can sound so smooth that it becomes homogenizing and bores you to sleep. The Ayre KX-R Twenty was able to both uncover the most minute details within recordings while keeping intact -- and then some -- that utter listenability that Ayre is known for.

I’d love to tell you exactly why the KX-R Twenty sounds the way it does. For example, superior sound is often attributable to lower levels of noise. I’m not sure if Ayre is claiming any improved specifications for the Twenty -- in other words, better measurements. The original KX-R was profoundly silent between notes. The Twenty is, too, but also seems to let through more music -- just the opposite of how some poorly designed, high-feedback components sound. Listening to the Twenty, I never had the sense that the music was being held back by clogged-up circuits. Could this be the lack of timing-related distortions, which are minimized in no- and minimal-feedback designs? It’s all speculation at this point, but I’m sure there are multiple reasons why the Twenty sounds better than the original KX-R. Remember, the Twenty includes multiple parts upgrades and revised circuits.

At the end of the day, “Let Her Go,” from Passenger’s All the Little Lights (16/44.1 AIFF, Black Crow), sounded rhythmic and flowing, showcasing that spectacular liquidity. The a cappella ending was downright spooky in its palpability, Michael David Rosenberg’s lyrics coming through the system completely unfettered by any vestige of electronic haze. The acoustic version of “Titanium,” from Madilyn Bailey’s The Covers Volume II (MP3), was enjoyable despite the limited resolution. And the listening went on . . .


It stands to reason that if Ayre Acoustics’ original KX-R was the best preamp I’d ever had in my system, and the KX-R Twenty is even better, then the KX-R Twenty is the new “best preamp I’ve ever heard.” It is. I used the Twenty in a system that acts as a microscope on my recordings, and I heard no shortcomings in the Ayre. Smooth, revealing, neutral, utterly effortless, liquid -- it does it all.

Ayre KX-R

In my opinion, the original KX-R eclipsed the sound of Ayre’s excellent MX-R mono power amplifiers -- the two are natural partners in the Ayre lineup. Now that the KX-R Twenty has stretched that lead even further, the challenge for Charles Hansen & Co. is how to improve the MX-R when its Twenty update is released, shortly after this review is published. I hope they can do it. But until that happens, my skeptic’s hat is back on.

Regardless, Ayre will still have the KX-R Twenty as high ground to stand on for years to come. To my ears, the KX-R Twenty is at the very top of that mountain -- and the view is just terrific.

. . . Jeff Fritz

Associated Equipment

  • Speakers -- Magico Q7 and S1
  • Amplifiers -- Ayre Acoustics MX-R monoblocks
  • Preamplifier -- Ayre Acoustics KX-R
  • Sources -- Apple MacBook running OS X Snow Leopard, iTunes, Amarra 2.6; Resonessence Labs Invicta Mirus and M2Tech Young DSD DACs
  • Cables -- Nordost Valhalla interconnects, speaker cables, power cords; Siltech Explorer speaker cables, interconnects, power cords

Ayre Acoustics KX-R Twenty Preamplifier
Price: $27,500 USD.
Warranty: Five years parts and labor.

Ayre Acoustics, Inc.
2300-B Central Ave.
Boulder, CO 80301
Phone: (303) 442-7300
Fax: (303) 442-7301

E-mail: info@ayre.com
Website: www.ayre.com