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If the world didn't suck, we'd all fall off. That's how 6moons writer Stephæn signs his e-mails to remind himself and us that nothing is perfect. Reader Alex wrote in opining that "this Esoteric piece is small, stylish, of modest but not flea power, its DAC is presumably going to better those of most computers, and even the provision of tone controls are most welcome for nearfield listening, including at lower volumes where one could dial-in a little loudness compensation of sorts. Just a few shortfalls: The price! ('nuff said); I'm not completely sure, from either your article or the Esoteric website, whether this unit is capable of internally reclocking any old digital input -- it sounds like maybe not -- but if it could that would be absolutely ideal for a desktop application; and while they've definitely packed a lot into a small space, Esoteric really should've included a headphone output, both for Japanese apartment dwellers and for my use."

To test the AZ-1's internal DAC, I opted for the Raysonic Audio CD-128 and Ancient Audio Lektor Prime players as two different sources priced at $1,690 and $9,800 respectively, both of which offer S/PDIF digital outputs. Serguei Timachev's Stealth Sextet would do the digital cable honors. To evaluate the preamp/amp circuitry, Bel Canto Design's PRe3/S300 combo would stand in as an ICEpower'd Class D comparator. For speakers, I had both the 97dB WLM Diva Monitor and the 82.5dB Mark & Daniel Ruby with OmniHarmonizer at opposite ends of the power drain scenario.


First impressions over the Diva Monitors centered on the over abundance of detail embedded in a positively gargantuan soundstage. Secondary and tertiary data such as wind noise escaping a clarinetist's lip seal, key clacks, reed buzzes, finger slides on strings and such were given equal treatment to the foreground action. This made for photographic hyper realism, with the endless depth of field where foreground and extreme background are equally and microscopically resolved. All the usual background data materialized as up close and personal as the primary stuff. This revolved particularly around transients in the lower treble to spike up the presentation with top-end energy.

The 'artificial intelligence' aka non-linear distortion behavior of superior single-ended valve amps has a very different sorting mechanism whereby the close-up stuff comes closer and the secondary stuff remains secondary. Needless to say, this rather shifts perspective on the same piece of music. It's obvious that if you come from the SET milieu, this type of equalizing the usual priorities of musical importance -- very different from the Tripath-powered Red Wine Audio Signature 30 and Firenze Audio Rosso 460B by the way -- will telegraph as nearly detail overload at first. I use the term eq'ing deliberately. Compared to live music, that's exactly what it is. It's an idealized bird's eye view which, figuratively, glues the listener's ears to various mikes suspended from the ceiling directly above the musicians. No living being would ever find itself enjoying a performance from that close-up and massively paralleled a vantage point. In short, it's not entirely natural.

That of course doesn't mean you couldn't enjoy it. Au contraire. After all, the playback experience always happens minus one - without the benefit of eye sight. Moving the background stuff "equidistant" to the foreground stuff makes you see more, making up for the lack of visual data while you listen to a CD. I'm not sure what, outside of steep slew rates and super low noise floors, is functionally responsible for this behavior. Its effects are blatantly obvious however.


Another unusual effect especially for a triode listener like myself is the transient linearity in the low frequencies. Leading edges in the bass and midbass become more wiry and pungent just like the remainder of the audible band which, besides the transient energy in the lower treble, further compounds the perception of intense detail. Listening over the AZ-1 becomes a highly visual experience. The side effect for me was a reduction of emotional involvement, perhaps because involvement thrives on active participation. When everything down to the tiniest speck is spelled out so blatantly and dry, nothing is left to the imagination. That somehow places the full burden of conviction on the system rather than keeping the listener involved in cocreating the experience. And with that, something inside capitulates. The enormous detail speaks for itself rather than serves the musical message.

In that sense, the AZ-1 is ultra-modern. It's like the dresses at the annual Oscars. They likewise leave nothing to the imagination to kill off romance. Here, spiky transients shoot up all over the soundstage with vigor -- some might say near relentlessness -- and the blackground is exceptionally inky to make for an intense contrast ratio. Images pop out and jump factor is high. Upper frequencies aren't bright per se but certainly forward, tracking the smallest swishes of brushes, the tiniest clacks of metal objects. Put plainly, it's a very transient-led presentation, with less apparent weight on the ringing out of tones. Anything rhythmically charged gets taken for a wild ride. While not entirely realistic unless one listened to live music on stage or from the conductor's chair, in the right frame of mind it can be quite addictive.
All this being so apparent already on the 10-inch widebanders of my Diva Monitors, I was curious what the twin air motion transformers and small but long-throw underhung mid/woofer of the Mark & Daniel Rubys would make of it.

Exceptionally well-damped bass. The ficus and palm are three feet behind the Rubys but the leaves were a'shimmying whenever bass notes of sufficient amplitude exploded through the micro rear ports in sharply focused jets of compressed air. Minus 20 on the Esoteric's dial equated to happy levels for my room and ears, with headroom to spare. Whatever concerns the AZ-1's power specs on paper may seem to have justified proved entirely unwarranted. B&W 805 owners of the non-headbanging persuasion in sanely sized rooms are more than in business with this single rack space low rider.


Not only are the desired SPLs gushing forth unrestrained from less efficient speakers, there's no apparent lack of control or damping, this likely due to a vanishingly low output impedance. Though I wouldn't have expected it, this combination sailed at full speed and would have dropped a few jaws. Perhaps due to avoiding beaming -- the dual-concentric 10-inch array of the Diva Monitor naturally beams -- the Rubies were less rather than more guilty of emphasizing the non-SET traits of the Esoteric integrated listed above. This caught me by surprise but there it was and my ears were nodding in agreement. The question of raw grunt settled, it was time to compare the Bel Canto Duo to the one-box Esoteric since the former have been reviewed a lot and present a somewhat known quantity.

The boxes from Minneapolis were clearly warmer, less pushy and less spiky. The transient heat of the AZ-1 mellowed out and the sense of little doors popping open all over the soundstage, with little cuckoo alarms of tertiary incidents and events going off, relaxed back into something more natural. The lower midrange / upper bass band of the Americans was weightier and denser to somehow enfold the leading edges and render them less forward. This also proved the case in the 40-80Hz band where transients were less wiry and striated - more natural to my ears. The whole acoustic center shifted downwards and with it, the treble presence of the Japanese contender.


As my comments show, the AZ-1 bore no resemblance whatsoever to any tube amp I've ever heard. Approaching it from that perspective is bound to miss it then. It's not that the treble is bright. It's very incisive and thus subjectively forward and rather the opposite to valves. Equally different is the resorting of sub information in the same perceptional plane by which I don't mean a spatial foreshortening. The soundstage is suspended well behind and above and even outside the speakers were it belongs. It's the tiny technical stuff of how an instrument is handled or a microphone excited that's presented in full-on focus. It suddenly becomes as important as the melody or walking bass line. And for my sensibilities, that stuff isn't as important nor should it be. I don't particularly cherish feeling as though I was staring down the throat of a singer. Or feeling like an ant on a clarinet, seeing a key come crashing down with great force right beside me and peering through a key hole to see the spittle running down inside the blackwood. If you're a very visual listener however, this type of presentation could have your name written all over it.


On a side note, my particular residency in Cyprus means higher than standard wall voltages. Some transformers don't mind over-voltages, others do and buzz. The first AZ-1's transformer minded. In my digs, fed essentially straight from the wall through a passive Furutech RTP-6 outlet multiplier, it turned into a non GM hummer audible in the listening seat. Engineering in Japan insisted that wall voltage shouldn't elicit a noisy response and dispatched a second unit which proved perfectly quiet just like prior Esoteric digital reviewed in the same space. The first loaner's transformer simply seemed a bit out of spec. I appreciated the company's diligence of sending a second amplifier to settle that question.

On the DAC comparisons, the Lektor Prime's 6H30-based output stage was softer in its handling of transients -- clearly apparent on sibilants -- and far more dimensionally textured than the AZ-1's own DAC which was drier and sharper, with less audible space and a more matter-of-fact presentation. The difference was most notable in the amount of recorded reverb, the spider webs of decay trails intersecting space which was emptier and blanker with the AZ's internal DAC handling data processing. The difference became nearly more pronounced with the Raysonic CD-128 which I admittedly run with rare Mullards. Call it tube distortion, call it tone color, call it greater body - however you reference it, the analog feed had it, the digital feed handing over analog duties to the Esoteric didn't. While not as resolved as the more expensive Polish player, the Canadian/Chinese contender had greater image density which, in this context, was good medicine. Consider this take on things my own personal long-term damage from diehard thermionic allegiances.


Conclusion
As an integrated amplifier, Esoteric's AZ-1 faces stiff competition from the Bel Canto Design PRe3/S300 combo. That comes in at $500 less, 100 watts more and doesn't push ultra resolution into cool and aloof hyper realism quite like the AZ-1. Hence even a value champ like Raysonic's $1,690 CD-128 valved disc spinner could impress listeners more in this context than the AZ-1's own DAC. If so, it'd make its inclusion for advanced 2-channel listeners less of an attraction and a redundant feature.
As it stands, this is the first Esoteric product I've reviewed which I didn't find to be at absolutely the very top of its class. Perhaps at this time,
digital indeed does remain this company's core competency? Based on my first encounter with an Esoteric amplifier, I can't be sure but have to confess to suspect as much. Should Esoteric USA decide to import the big A70 Class A monoblocks, I could well be proven wrong however...
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