Art Dudley returned to the Air Tight ATM-300R in November 2019 (Vol.42 No.11):
Nine months ago, while I was busy reviewing Axiss Audio's Air Tight ATM-300R single-ended power amp ($16,995 with Electro-Harmonix output tubes), my new old house was still new to me, and I hadn't succeeded at getting my 1966 Altec Flamenco loudspeakers to sound consistently good in its 11' by 16' living room. So before I made my listening notes on the Air Tight, I banished my Altecs to the garage—temporarily, of course, until such time as I knew how to get them to sing in their new setting—and relied instead on my DeVore O/93 loudspeakers, which took to my new living room like Unitarians to a vegan picnic.
Not long after, I hired a contractor to remove a closet from the house's family room, an alteration that netted me a 12' by 17' space in which my playback system sounds much better—even my Altec Flamencos, freshly back from exile. Indeed, in this space, the very large Altecs were less finicky than in my previous home: Here they exhibited a surprising ability to sound their best when aimed straight ahead (ie, no toe-in), ultimately rewarding me with a larger-than-ever sense of scale and smoother upper mids and lower trebles when heard from a more or less centrally located listening seat.
Because the single-ended ATM-300R has a rated power output of only 9Wpc, and the Altec Flamenco has even higher efficiency than the DeVores, there was no way I could send the former back to its distributor without trying the two products together. The combination proved a brilliant one, the Air Tight Amp sounding a little less rich than my Shindo Haut-Brion but offering greater spatial depth and, more important, tighter, snappier musical timing, especially on lower-pitched instruments.
Returning to a record that featured prominently in my original ATM-300R review, the Georg Solti/Vienna Philharmonic/Kirsten Flagstad et al recording of Wagner's Das Rheingold (3 LPs, London OSA 1309), the Air Tight performed brilliantly. It found on this recording, and coaxed from my Altecs, a heretofore unheard degree of stage depth—yet when the voices in the first scene were upstage, the positions of those singers and the physicality of their voices were well defined. By comparison, my Shindo Haut-Brion, though superior in the degree of thrust it gave to cellos and double basses, sounded spatially vague. String texture through the Air Tight amp was to die for: generous but not exaggerated, and allied to gorgeous, realistically rich timbres, especially the violins.
Most important of all, the Air Tight rivaled the Shindo in presenting this recording not as mere (attractive) sound but as music. Listening to the introductory bars with the Air Tight amp in my system, the timing was clearer than ever: Rather than getting lost in a mushy maelstrom of sound, the entrance of each instrument/group was as precise as it was hypnotic. And for once the first Rhinemaiden's entrance didn't surprise me: Because I found it easy to follow the beat through this temporally clear amp, I knew right when it was going to happen.
Really: If I wanted to show someone what's special about this John Culshaw-produced recording, I would play it for them with the Air Tight driving my Altecs.
Through the combination of Air Tight and Altecs, yet another classical recording proved revelatory: Nathan Milstein's recording of the Bach D-minor Partita from his box set of the complete Sonatas and Partitas (3LPs, Deutsche Gramophone 2721087). It's a very reverberant recording— whether naturally or not, I have no idea—and especially on an up-tempo movement like the Gigue, that quality can compromise the momentum of the performance: the sense of the player leaning into the music. With the Air Tight in the system, I heard momentum and drive like never before; compared to my Shindo amp, I was getting less room and more fiddling. On top of that, Milstein's more forceful note attacks in the famous Chaconne sounded downright fierce.
On the Sir Adrian Boult/New Philharmonia recording of Elgar's The Dream of Gerontius (2 LPs, EMI SLS 987), when the priest (bass Robert Lloyd) enters at the end of Part One, the effect through the Air Tight was magnificent. Lloyd's voice sounded rich, clear, and powerful, and was presented in a manner that was considerably more spatially complex, for want of better words, than through my Haut-Brion: There was space around his voice, and I could sense if not quite hear the locations of the instruments behind him—a strange thing indeed. The sense of scale was perfect: On this track, orchestra, soloist, and (eventually) choir were every bit as huge as they should have been.
But, again, that's just sound; more important was the Air Tight's musical acumen—the way it made clear the dramatic tension when Lloyd drew out the end of the lines "de hoc mundo" and "Go from this world": The effect was breathtaking.
The Air Tight/Altec combo proved no less capable with rock and jazz. On Procol Harum's "Butterfly Boys"—the best-sounding track on the generally well-engineered Exotic Birds and Fruit (LP, UK Chrysalis CHR 1058, footnote 1)—the ATM300R equaled my Haut-Brion in texture, color, musical timing, and sheer force, and added greater insights into the sounds of the instruments, especially the wheeze of Chris Copping's Hammond organ/Leslie speaker combination, and the ever-moving, ever-changing patterns that Alan Cartwright plays on his Fender Precision bass, in great part the real driving force behind this up-tempo number.
The only track on which this amp didn't shine completely was "Hat and Beard," from Eric Dolphy's Out to Lunch! (2 45rpm LPs, Blue Note/Music Matters ST-84163). The sounds of Bobby Hutcherson's vibes bloomed colorfully and had perfectly balanced note attacks, and Richard Davis's often complex double-bass lines were laid out clearly. But all the instruments, especially Dolphy's bass clarinet, sounded a little smaller than they should have. By comparison, my Haut-Brion was a bit bigger and, for want of better words, friendlier and more inviting: It made more sense of this challenging music.
In the wake of my original review, Air Tight's US distributor agreed to try to supply a loaner pair of the premium-quality Takatsuki TA-300B output tubes that Air Tight offers as an extra-cost option. (New ATM-300Rs retail for $19,995 when supplied with the Takatsukis.) Unfortunately, that never happened, but I did try a pair of Gold Lion PX300B tubes I had on hand: easy enough to do, given the ATM-300R's auto-bias design. (Rather than applying to the signal grids a fixed negative voltage—the very thing that requires precise setting and adjusting in fixed-bias amps— Air Tight connects the grids to ground and uses a resistor to raise the positive voltage on the cathodes.) I heard little if any audible change—if anything, the trebles were very slightly grainier with the Gold Lions. People whose opinions I hold in high regard have praised the Takatsuki tubes, so I won't rule out the possibility that they might allow the Air Tight amp to sound even better.
And as it stands now, the ATM-300R is already a fine-sounding amp—exceptionally so, in the truest sense of that word. When paired with sympathetic (read: high-efficiency) loudspeakers, this heirloom-quality artisanal amplifier stands with a select few that can reasonably be regarded as the best.—Art Dudley
Footnote 1: But oh! the heavy-handed reverb!
Footnote 1: But oh! the heavy-handed reverb!
