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Reviewer: Frederic Beudot
Financial Interests: click here
 Digital Source: Mac mini, Burson HA-160D, Burson Conductor, Metrum Hex [in for review], Audioquest Carbon USB cable, Ocellia USB cable
Analog source: Acoustic Solid Classic Wood, AS WTB211, Dynavector DV20X-2, Esoteric E03
Preamplifiers: Burson HA-160D, Burson Conductor
Amplifier: FirstWatt F5, Yamamoto A08s
Speakers: Zu Essence, Ocellia Calliope 0.21 Twin Signature
Headfi: Burson HA160D, AKG K701
Signal cables: Zu Varial, Genesis Absolute Fidelity (Speaker), ASI Liveline
Power Cords: Zu Mother, Genesis Absolute Fidelity (Power), ASI Liveline
Powerline conditioning: Isotek Nova
Sundry accessories: Isolpads, ASI Heartsong racks
Room size: 12.5' x 18' x 8'
Review component retail: Depends on country, regional VAT and customs to likely be $4.900 in the US

As announced in Srajan's review of the Yamamoto A014, I had the chance to live with one for a few weeks to pen this follow-up commentary. My review sample shipped brand new from Japan to their Canadian distributor Ateliers Audio and then directly to me. This meant that both amplifier and Emission Lab 300B XLS needed a few weeks and thermal cycles to settle down and drop their initial brightness. The NOS 5U4G rectifier shipped with the amplifier proved unusually noisy at startup as well as extremely microphonic. I first thought the amplifier had been damaged in transit but a replacement tube shipped within a few days quickly addressed the problem.

Srajan's description was right on. Whoever owned a Yamamoto before will immediately notice the concessions on finish and connectors that enabled the almost 50% price reduction between A09s and A014. Most notable is the disappearance of the positively gorgeous impregnated Cherry wood of earlier models now replaced by veneered Ply as well as visible screws on deck. That said, for anybody else without such a reference, it's still a very well finished elegant piece of gear that won't look out of place in most systems. I should however mention that the meter on my review sample was labeled "Driver Stage Boltage" instead of voltage, a discreet reminder of the fully artisanal nature of production at Yamamoto. Despite my admiration for Yamamoto electronics, I need to start this review off with a few provisos. Most of them have nothing to do with sound quality so I gather them upfront simply to let you know whether they'd be an issue for you. If not you can keep reading past these bullets.

• As Srajan accurately described the new clearly lighter speaker terminals do not accommodate even fully extended bananas. The opening is simply too wide. You can connect slimmer bananas using the holes meant for non-terminated wire but it'll be somewhat awkward.
• Quite typical for the 300B SET breed, the A014's self noise is audible from the listening seat with higher sensitivity speakers. The Ocellias are rated at about 97dB. Here tube rush was inescapable so I can only guess how unacceptable it would be on 104dB horns. The noise level from this Yamamoto was higher than with any other tube amp on hand or recently reviewed. The Triode Lab EL84 integrated is my reference for probably being the quietest valve amp I've ever assessed but even the Yamamoto A08s with its 2 watts of 45 direct-heated triode goodness or Ocellia's own 300B integrated were both significantly quieter than the A014. On most SET amplifiers noise cannot be heard while music is playing. With the A014 noise was present during low-level passages which abound in classical music.
• Clearly the volume control in the A014 is meant to be used. It cannot really be bypassed. If you increase volume past 10/11 o'clock on the dial without signal, you'll be rewarded with increasing noise levels that eventually go beyond acceptable and decrease playback quality. The only reason why this matters is related to my next point of contention. The A014 only offers a single input. I have 2 sources at all times (converter and vinyl) and sometimes a few more under review. Despite its supposed purity superiority, a single input design becomes a clear limitation and would be to anybody who doesn't enjoy swapping cables with every source change. The solution would be to introduce a preamplifier ahead of the A014 for source switching—preferably a passive to not add noise which is likely exasperated by the Yamamoto's high gain—but two volume controls in series aren't exactly aligned with my idea of purist audio gear.

As I wrote, none of these points are absolute show stoppers. They simply need to be factored into any purchase decision. If you can live within those constraints, the A014 is a contender when it comes to delivering the full-on 300B SET experience. Voices seem to float three-dimensionally in the middle of the room unattached to anything material. The soundstage is expansive and the music flows fluidly and elastically as though it had all the time in the world to develop those harmonics and decays to your heart's content.

The use of Emission Lab's modern 300B XLS bottles yields slightly sharper transients and better bass control than your average NOS Western Electric or its modern reproductions whilst still remaining within the general 300B aesthetic. It also yields a slightly more lit-up upper midrange that is not quite as rich, natural and full but whose openness will serve denser speakers like Zu even better than it did my Ocellia Calliopes. Over a few weeks I was able to spend time listening to the A014 alternating with my FirstWatt F5, Yamamoto A08s and the Triode Lab EL84TT loaner. Here is how they compared.