Tube Power Amp Reviews

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.

Listening
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.

Conclusions
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.

Nothing.

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.

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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.