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Perfection exists in many forms. Common to all is absence of lack. In audio, perfection comes in discrete flavors. A perfect adrenaline system for example sounds very different from a system that's been dialed for perfect transparency. Yet to owners matched properly to their respective qualities, both would leave nothing to be desired. While quite different, they'd be perfect. Complete. In balance. Two flawless perspectives of many possible others.

The YDA-01 inspires such musings. It is shockingly good. In my present system, it achieves a very compelling form of perfection. However, in material reality -- which bites -- it's not quite complete. While I appreciate that it was omitted on price, an asynchronous USB receiver module and input would exponentially increase its appeal. Let's hope that an eventual YDA-02 will add this feature, sticker hike be damned. MacBook transporters and other streaming listeners really deserve to hear this machine, too.

While still on material reality, I can't say that I heard the effects of mass-loading the top panel with a few double-thick Walker Audio lead-filled brass discs. But it's undamped ringiness will bother the obsessive compulsive crowd as an unnecessary blemish on an otherwise immaculately crafted machine. To maximize pride of ownership, Yamamoto could apply an internal damping sheet and control that freely resonating top panel.

After 24/7 operation over 10 days, the YDA-01 called out to be pitched against my best digital, the massive and painfully priced APL HiFi NWO 3.0GO with its 20 paralleled 32-bit AKM chips per channel. While trophy hunters will swallow hard (they assume only über prices can generate peak performance), the Yamamoto wasn't embarrassed in the least. In fact, I preferred it. It better fit my present rig's aural aesthetic. Let's talk about that for a moment then.

As mentioned elsewhere, Franck Tchang of acoustic resonator fame recently treated our house with the inventory of acoustic tools from our prior Cyprus residence. In a tag team effort, he also set up his Tango speakers whose stupendous resolution particularly in the upper harmonic realm guided placement of the resonators, noise filters and mechanical phase inverters. The resultant system -- a very long, highly assymmetrical space with an 8-meter depth of kitchen, dining space and office behind the speakers, with the APL Hifi/Esoteric as source, a ModWright LS/PS 36.5 preamp and a FirstWatt F5 or Yamamoto A-09S amplifier wired up with ASI Liveline cables -- is my present idea of perfection in the 'I am there' rather than 'they are here' class. There is extreme low-level resolution, terrific depth (such a setup will do that each time) and harmonic purity and finesse of a kind I've never enjoyed before.

The overall sound is on the lean, fast and lit-up side, with even bass extension solidly into the mid 20s. You hear everything. Layering is heightened, soundstaging wall to wall and addiction to high volumes undermined by crystalline clarity at whisper levels. If the F5 runs the show. The tube amp's intrinsically higher noise floor has it kick in a bit later. Sophisticated timbres with highly developed harmonics and superb timing are the core virtues here. Think lightness of being, breath of life and intense transmission at higher levels. The presentation is very airy and 'slightly' cerebral, i.e. not as emphasized on density, mass and macro jump factor as the ZU/WLM aesthetic I pursued previously. But resolving power is quite a bit higher, perfect also for my reviewing gig. It's simply taken me this long to chance upon a combination that performs more microscopic duty and continues the musical pleasure giving.

As my review of it detailed, Mr. Peychev's rebuilt UX-1 with its top-line VRDS sled majors in correcting what is wrong with digital treble. I called it the removal of sting. Think Zanden gestalt liberated into the stratosphere of extension. Frederic Beudot on staff described a similar treble naturalization during his review of Esoteric's D-05 DAC. The connection to the Peychev version is the same dual-diff AKM AK4397* 32-bit chip. Frederic and I thus consider it the primary suspect for this pellucid treble quality which is both gentle and fully resolved.

If Shigeki-San were to ask me for engineering advice on the YDA-01 (he clearly doesn't need it nor would I be competent to give any), I would suggest he at least investigate the AK4397 if he hasn't already. There's something special about it and it's worthy of conjecture to wonder how his I/V conversion and output stages would sound with those chips.

As my system is currently voiced, the single-ended transistor YDA-01 is more vivid and virile than the NWO with its ECC99 output stage. That creates grounding and gravity. It counters a trend towards the transcendental when the Peychev machine processes the digits. A contributing factor just as Shigeki-San proposed is his converter's potency in the nether regions. Surprising perhaps to those who know Peychev's somewhat bullish self confidence, his equipment is a bit light down low - very refined but not ultimately anchored. That's particularly true for his Bada platform amplifier but it remains operative in the NWO. That surfaces consciously against the Yamamoto.

The latter thus introduces more tensegrity. It's the principle of opposing structural forces whose absence has material or organic forms collapse. Relaxation is good. Too much lacks spine and spunk. Musicians translate tensegrity as "things hanging together" or "playing in the pocket". And the YDA-01 transmits that inner excitement better than the 10 times plus priced NWO in how my system currently sits. Enter rumination two to cover the next aspect.

Without conscious volition, my resident harem of exclusively one-box disc spinners glows in the dark, no exceptions. From Opera Audio's top Linear player to Raysonic's CD-168 to the 6H30-stage of the Ancient Audio Lektor Prime and the APL, each machine sports a tube buffer. The Yamamoto does not. As I hinted at in the A-09S review, regardless of output tube -- I tried from EAT to two EMLs to JJ to TJ to WE -- the Nelson Pass amp has more resolution. I suspect it's quite simply measurably lower in noise. And I suspect the same holds true for the YDA-01.

It's become popular for digital makers to furnish ever-increasing S/N specs. Besides certain limitations imposed by math, there are others imposed by circuitry. While a D/A converter chip measured at its pins might indeed measure accordingly, by the time you add a tube buffer and measure again at the analog outputs, you'll surely be far removed from theoretical perfection. On the evidence of the YDA-01, I'm asking myself whether in a digital source, running tubes (which are S/N challenged compared to transistors) is desirable if, a/ your circuit doesn't call for a valve smoothing action because it doesn't misbehave in the first place; b/ you want to hear it all; and c/ you accept the logic that anything lost at this stage can't be recovered.

While flying in the dark compared to all my glowing machines, the Yamamoto's ambient retrieval and dancing with the gossamer stuff is truly fabulous. Just as going from the A-09S to the F5 does, going from any of my valved players to the YDA-01 pays dividends in this area. And because we're dealing with the really small stuff, it doesn't take big steps to notice advances. Again like transitioning from the A-09S to the F5, there is no loss of elegance, no drying up. To be sure, something is removed - something between and around the notes. While clearing up and thinning out in the process, things don't crystallize. They don't produce the sharpness we equate with edges which we then call digital.

The tube-buffered digital outputs produce a mellowing action. My present assessment is that the system in Casa Chardonne as described above no longer needs it. I can see John Stronczer of Bel Canto Design nodding, thinking to himself "that only took you six years". Over quite some time, we've had an on/off dialogue about his abandoning tubes in favor of class D and how that informed his subsequent audiophile career. And how my ongoing fascination with tubes maintained a perceived need for them at least somewhere in the chain. And I'm still not entirely cured. There's 6H30s in the ModWright and plenty of tubes in its power supply. Nor am I abandoning my A-09S for the F5. Both presentations are beautiful. I love them each for their unique flavor. But I've come to a point where there needn't be tubes in the source or amplifier to be deliriously thrilled. Linear progress? Circular wanderings? Lost in the wild altogether?

To such open-ended questions, I do want to add that in my experience, it is far easier to assemble a musically satisfying system around tubes than transistors. Clearly it can be done with transistors, perhaps even exclusively (I'm not there yet). Having been modeled by consistent involvement with valves however, it's proven far more elusive with solid-state for me. My conversion occurred with FirstWatt, particularly from the F3 amplifier onward to the F4 and now F5. I've reviewed and subsequently used them all. Yamamoto's YDA-01 is a personal second-coming conversion. Doubling back to its single-ended no-feedback circuit past the D/A conversion stage, perhaps that shouldn't be surprising? A very simple fast wide-bandwidth circuit with inherently low distortion to require no corrections has much merit. That could be senior in import over whether a lone tube or transistor sits at the output.

Compared to the Raysonic CD-168, there's really no comparison. The YDA-01 works from a higher plateau. If its performance, as the designer believes, is partly due to avoiding high-feedback op amps in the I/V conversion stage, then the Raysonic's op-amps followed by tubes might look like a very confused recipe; one which attempts to 'fix' the dryness and timing errors from heaps of feedback with the smoothing action of a valve buffer. However, the CD-168 does make for a highly credible transport. Its trailing as a transport, of the PRO-2 equipped Ancient Audio machine or the mighty Esoteric, is far smaller in percentage points than its analog outputs are overshadowed by the Yamamoto's. It doesn't take a silly money transport then to get most of what the YDA-01 is capable of. Nor does it take an exotic S/PDIF cable. The €300 ASI Liveline is what I used and I know how it outperforms far more expensive cables in my arsenal.

What we have here then is a minimalist-featured and as such endangered-species component of exceptional merit. While I'm surprised by the timing of its launch, I am even more surprised by its performance. Well, perhaps not entirely. My introduction did paint me as an admirer of Shigeki-San's work. Unless guilty of an outright mistake, someone whose ears so clearly agree with yours should be incapable of creating something you wouldn't appreciate. My surprise then is more due to my thermionic conditioning which expects less from transistors. And just maybe, it does take a dyed-in-the-wool valve designer to use transistors in an 'emulative' fashion that would appeal completely to other valve lovers.

Here's what the YDA-01 is not: mechanical, dry, sterile, flat or even hyper-realist (to throw in a possible class D phenom). Nor is it warm, romantic, soft or 'enhanced'. As much as can be ascertained from any given component which only makes sound in tandem with others, the YDA-01 is organic, very resolved, tremendously refined and informative in the treble, liquid rather than dense, with very good timing and powerful bass. It's neither limpid nor agitated but has the kind of perceptive drive that creates cohesion from musical parts. However, it's not focused on extreme dynamics like the Stylos Sys Had or Stahl-Tek Vekian nor on the density of the Red Wine Audio Isabella. And, it seems entirely unfussy in operation. To close out, here's another personal bias and how it relates to this piece.

The best music occurs when the performers' personalities submerge in the way of spontaneous inspiration, what I think of as transmission or channeling from elsewhere (higher self, group mind, the creative principle, take your pick). Having been a performing musician, I can attest how strange many of them are as people. When I turn on my system, I don't want to 'see' performers. I care nothing for thinking I have strange people in my living room. What I care about is listening to music. That's a transpersonal matter. The visual cues that nearly prompt seeing are neither important nor desired. What's important is the removal of barriers so I can easily connect with the emotions carried by or on the music. The more powerful those emotions, the less they have to do with a performer's personality in the first place. Let's leave the performers and beaming them into the room out of the equation then. Focus on the message. The messengers got paid already and long since took off to new projects.

That's also why I close my eyes. The sensory energy usually rushing through the eyes is available to the ears. With the eyes and ears being our two keenest senses of five, it is peculiar how unlike our eyes, we cannot close our ears. Deep asleep, a sound can wake you while a carefully quiet thief can perform his mischief right in front of you eyes shut and fear no detection. The kind of sound you can achieve with the Yamamoto YDA-01 very much lends itself to the listening type of feeling connectedness. Audiophiles who fancy a listening-with-the-eyes mode to create the illusion of actual people in their space -- the 'they are here' ideal -- will prefer something else. That's why higher up on this page, I mentioned different forms of perfection. They all co-exist. As multi-dimensional beings, we have the capacity to enjoy many of them on their own merit.

With the Yamamoto YDA-01, I predict that many tube lovers will. 'Their' virtues of non-blunt immediacy and emotional intimacy are right there. However, resolution exceeds equivalent tube circuits. Considering how we're dealing with the source, I tend to believe that's a good thing. All that microscopic stuff making up overtone structures, decays and faint but recorded boundary reflections can't be processed later if it's gone missing or was captured incompletely. You could thus call the YDA-01 a component by a tube lover for lovers of tubes which simply omits the tubes as not needed. If you've ever suffered angst over valve aging or that most inconvenient sudden death when spares weren't at hand... then you'd not blame this converter but applaud it. That's the position I find myself in, unexpectedly.

didn't award the Yamamoto A-08S 45 SET because its 2 watts make it a fringe player in an already small niche. I didn't award the Yamamoto A-09S  300B SET because its 8 watts are still too few for the vast majority. I was about to apply the same thinking to the YDA-01 because there's no USB connectivity. But then I did the math. How many people still use CD or DVD players? A lot. Replacing a CD player for a much better one is a tough proposition in these days. Streaming media, laptop servers and USD DACs offer so much more convenience and high performance for less money. But upgrading a still operational trusted player to eliminate its op-amps and inferior output stages remains relevant. And for the performance it delivers, the YDA-01 is a true find. For less than $3K (I threw in Franck Tchang's Liveline as digital interconnect since you'll need one), one gets true ultra performance for non-excessive coin.

That qualifies for an award. The perceptive reader will also appreciate how without special captions, this award simultaneously reflects the parallel achievements of the two Yamamoto amps I mentioned a moment ago. In fact, this converter is very much informed by them and indebted to Shigeki-San's decade of toil in the valve mines. Also, call it penance for my ongoing persecution of transistors (thus redeemed, I'm free to do more of it when it applies). As a product, the YDA-01 is relevant to a much larger audience than the Yamamoto SETs are, regardless of how much I'm smitten with those. That makes our special recognition of the YDA-01 all the more meaningful. That's why I wanted to single it out. Something here was overdue. I was merely waiting for 'mass appeal'. Yamamoto's first digital product is as close to that as it gets in this crazy and crazily overcrowded hobby of ours for such a specialty item!
Quality of packing: Very good.
Reusability of packing: Multiple times.
Ease of unpacking/repacking: Easy.
Condition of component received: Perfect.
Completeness of delivery: Power cord, copy of model-specific website info
Quality of owner's manual: Suffers software-generated translation.
Website comments: Needs proper English translations to be more informative for non-Japanese.
Human interactions: Always prompt and directly with the designer.
Pricing: Once again very fair for what your money buys in performance and build quality.
Final comments & suggestions: "First Watt goes digital." If Nelson Pass did a D/A converter for First Watt, this is what you'd expect. Those familiar with his F3 - F5 amps can transfer their sonics to the YDA-01 for a very close approximation.

Yamamoto website