Air Tight ATM-1S power amplifier Page 2

A final setup note: It didn't sound to me as if the ATM-1S inverted absolute signal polarity, but I've been wrong about that sort of thing before. Let's see what John Atkinson's measurements uncover.

Although it's difficult to say for sure without a blindfold and some 15-second snippets of unfamiliar music, it seemed to me that the Air Tight ATM-1S and my Shindo Corton-Charlemagne monoblocks, both of which use push-pull EL34 pentodes as output tubes, shared some common sonic and musical characteristics. Both were colorful, well textured, and slightly warm and lush, timbrally. And both allowed recorded music to have an appropriate sense of momentum and drive. Overall, if I were asked to sketch a quick-and-dirty thumbnail review, I'd say the Air Tight amp sounded like a musically tighter Shindo with a smaller sense of scale. Of course, one could turn that observation on its head and say that the Shindo is a bigger-, more fulsome-sounding Air Tight.

Another distinction: The Air Tight ATM-1S was almost uniquely capable of sounding forceful and present when listened to at lower volumes—which is to say, it was good at sounding loud without being loud. (Remarkably, the Air Tight required very little warm-up time before exhibiting that quality—something I noted while bearing in mind that my review sample was unusually well broken-in.) But when pushed to dynamic extremes—say, with well-recorded piano music—the Air Tight remained poised and free from gross colorations. With Vladimir Ashkenazy's recording of Chopin's Préludes (LP, London CS 7101), the Air Tight made musical hay of the pianist's forceful chording near the end of the middle section of the Prélude 15 in D-flat, while remaining clear of pitch and maintaining the recording's characteristically dry and pleasantly stringy piano sound.


The ATM-1S's ability to resolve subtle musical information was superb. Through it, the softest kettledrum taps and plucked strings in the opening of Walton's Violin Concerto, played by Ida Haendel and the Bournemouth Symphony Orchestra under Paavo Berglund (LP, EMI ASD 3483), were electric with impact—and the soloist's pizzicato notes early in the second movement sounded similarly, subtly forceful and engaging. The Air Tight also uncovered a wealth of subtleties from throughout the simply arranged and recorded John Wesley Harding, by Bob Dylan (mono LP, Columbia/Sundazed LP 5123). Especially through the DeVore O/96 speakers, the melodic and rhythmic intricacies of Charlie McCoy's electric-bass lines—as in the measures just before the final verse of "All Along the Watchtower"—gained exceptional clarity and musical import with the Air Tight in the system, and the curious gain-riding on Dylan's voice and guitar during many of the songs was easier than ever to hear.

Selections from Procol Harum's A Salty Dog (LP, Regal Zonophone SLRZ 1009), their most stylistically varied album, were very well served by the Air Tight. In "Too Much Between Us," Robin Trower's gently fingerpicked acoustic guitar had fine tone and very good pitch definition—and, even more easily than through the Shindo Corton-Charlemagnes, I could hear that the background voice in the final two lines of the chorus was that of none other than organist Matthew Fisher, singing "Mmmm." And in the punchy "The Devil Came from Kansas," Trower's electric guitar was . . . well, punchy, a quality shared by David Knights's full-sounding electric bass. During that afternoon's Brit-rock fest, I also heard no shortage of impact and touch in the sounds of the electric guitar and bass (footnote 2) in "Mr. Churchill Says," from the Kinks' Arthur (LP, Reprise 6366), the former instrument apparently strung with heavier-than-average strings and played with generous force.

The elegiacally beautiful "Warm Canto," from Mal Waldron's The Quest (LP, New Jazz NJLP 8269), presented both the Air Tight and Shindos with any number of sonic and musical challenges; ultimately, both amps allowed the music to sound emotionally and intellectually convincing, and both put across the sounds of the instruments—especially Ron Carter's plucked cello and Eric Dolphy's clarinet—with lots of rich, colorful, altogether beautiful tone. Beyond that, subtle differences emerged, especially in terms of pitch and timing: The Air Tight sounded more precise, with pianist Waldron's accent chords comprising notes struck at the exact same time, while, through the Shindos, the same chords sounded very slightly more arpeggiated, the result being a more complex, more textured sound. I can't begin to guess which is more "correct," but I'll risk the ire of more doctrinaire hobbyists by suggesting that I enjoyed both.

A final comparison centered around the Mozart à Paris box, issued in 1956 and reissued in 2012 (7 mono LPs, Pathé/Electric Recording Company DTX 191–197). As I listened to the aria "Popoli di Tessaglia," the Shindo monoblocks captured the clarity, directness, and surprising sweetness of this very dry recording, and allowed the high G sung by soprano Annik Simon—a fundamental of over 1500Hz!—to sound naturally piercing but not mechanical or harsh. Strings had gorgeous texture, especially in the final bars, and the performance as a whole was equal parts pretty and thrilling. The Air Tight ATM-1S told the same essential truths, while sounding slightly less rich than the Shindos and doing a more impressive job of thrusting Simon out in front of the orchestral ensemble in this mono recording. Both were a hell of a lot of fun.

My wife has a new shtick. These days, when I express my love for this or that inanimate object—my Hario conical-burr coffee grinder, someone else's two-weight fly rod, the yellow rain parka I thought I'd bought for myself but is now equally loved by the rest of the family—she replies: "Then I suppose you want to marry it?" I smile when I hear this, and carry on.

And so it was when I recently announced, "I'm really impressed with this new tube amp from Japan. It has EL34s and separate left- and right-channel level controls, just the way I like, and—"

I watched her face, waiting for it.


Maybe there was something in my tone. Something that said, I'm not just kidding around: I love this amplifier.

And I do. The Air Tight ATM-1S is right up there with the best I've heard: the artisanal, the small, the artistically sensitive, the colorful and characterful, the smart. At $9500, it isn't cheap. It isn't a toy or a half-hearted effort or an appliance to be used in the oozing of background music. The Air Tight is as serious an EL34 amplifier as I've heard, offering texture, color, poise, and musical drive and rightness, all in good proportion to one another. It also looks nice, and represents at least decent if not outrageously good value for the money.

In that most artificial yet most sincere of all review constructs, the Air Tight ATM-1S is among the few power amps I'd care to live with. Strongly recommended.

Footnote 2: The latter including what sounds like a Fender six-string bass, a pleasantly twangy but rich instrument with a voice all its own.
A&M Limited
US distributor: Axiss Audio
17800 S. Main Street, Suite 109
Gardena, CA 90248
(310) 329-0187

Rick Tomaszewicz's picture

My fave part of your reviews are the personal touches; of how our hobby interacts with the rest of our lives.

As the husband of a very understanding wife, I laughed at the SAF aside! (Any holiday in a foreign city must involve a visit to the best audio shop and a vinyl emporium.) Since cooking is her hobby, it takes no effort on my part to share her interest!

Although serious music listening tends to be a solitary experience, it takes up enough time (and floor area), that an understanding spouse is much appreciated.

tmsorosk's picture

On the contrary, I almost always listen with a friend, usually with the better half.
Can you think of a better way to spend an evening than snuggled up with the wife and a great recording ?

Rick Tomaszewicz's picture

you are doubly lucky to have a spouse who shares your taste in music, and to have a sound room big enough to fit a couch!

toon's picture

in the article it points out the "good-quality packing that allows the amp to be shipped with its tubes already in place". Then the problems with the left channel are said to be a result of the test unit being well traveled. Hardly an endorsement of the "good-quality packing that allows the amp to be shipped with its tubes already in place". And lets not forget the failure of one of the output tubes! On a $9,500 amp? I didn't realize being an audiophile involves masochism and self delusion.

John Atkinson's picture
Hardly an endorsement of the "good-quality packing that allows the amp to be shipped with its tubes already in place".

As Art pointed out, this was a much-traveled sample, with a misshaped top panel, perhaps due to being dropped. It had, we believe, been used at shows and by other reviewers before coming to Stereophile. The tube failure was therefore probably not typical.

John Atkinson
Editor, Stereophile

jmsent's picture

Why would anyone send Stereophile an amplifier so beat up that the top panel is bent and there's a bad tube in it? All you've got to show for it is a review of a broken amplifier. Someone at that distributor really dropped the ball on this.

toon's picture

Indeed. Art describes " the center of the top panel of my well-traveled review sample appeared to be sagging a bit under the weight of the transformers.". This after stating that "The quality of parts used in the ATM-1S is generally excellent, as is the internal build quality". Looks like Air Tight missed what would appear to be an easy engineering problem to fix. This leads me to assume that they missed something else, especially if the problem was less obvious and more difficult to fix than a sagging top plate. Maybe Air Tight can now come out with an SE model that contains a proper structural brace for the transformers. And they could then charge some ridiculous amount for the SE designated model. It wouldn't be the first time this has been done in the high end.

John Atkinson's picture
Why would anyone send Stereophile an amplifier so beat up that the top panel is bent and there's a bad tube in it?

We almost always get new, unused samples for review from US-based manfacturers. But with products manufactured overseas, the US distributor will often have a single sample that is sent out serially for review, to avoid the associated inventory costs of having many samples simultaneously out with reviewers. But they run the risk that a prior reviewer will have damaged the sample or that the sample will be damaged in shipping.

John Atkinson
Editor, Stereophile

T B Ong's picture

I've used a Air Tight ATC-2 and a pair of ATM-4 since 1996. They are extremely reliable, including the tubes. After 16 years, I needed to change a small capacitor on one of the power amp. An easy and quick fix.

corrective_unconscious's picture

"I didn't realize being an audiophile involves masochism and self delusion."

It also involves other, more positive things.

John Toste's picture

Thanks Art for giving some exposure to a great company. I used to sell them when I was in retail and have fond memories of the models 1, 2 and 3. They were then and are now preferable to many more well known brands.

Regarding your "usual practice of ignoring aftermarket AC cords" - seriously? It would be unlike you to let prejudice preclude useful experience. Would you care to explain your reasoning?

xyzip's picture

Japanese hifi-coffee shop. Hario conical-burr!

T B Ong's picture

I've used a Air Tight ATC-2 and a pair of ATM-4 since 1996. They are extremely reliable, including the tubes. After 16 years, I needed to change a small capacitor on one of the power amp. An easy and quick fix.