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A few things about the freshly landed Yamamoto. Ultra resolution, speed and a propensity for sounding very lit-up and forward in the upper midrange/lower treble are instantly apparent. Tonal balance is clearly skewed. However, detail retrieval such as apparently individual strands on a brush swirling on a cymbal; the slightly blocked nasal inhalations of a pianist you were only marginally aware of earlier; emphatic finger pressure on a particular ebony key or an especially vigorously popped growling bass string - the Yamamoto, to use vinyl talk, veritably digs into the grooves like a greedy claim jumper on the word go. It removes cobwebs and thereby retrieves the life between the notes, making it plain how capricious spur-of-the-moment humans play those instruments rather than programmed machines.


Right off the bat then, this modern tube amplifier gives away nothing to solid-state in the articulation department. But in so many ways, it also feels like the Anti Christ to the candle-lit romance that still pegs popular perception of direct-heated triodes. I initially didn't know how much time the amp already had on it. I found its 800 - 1,400Hz energy to verge on the painful. My first inclination is for copper - warming copper cables. The included Y-LC interconnect uses a solid 1.6mm 6N copper conductor inside a central Teflon tube. That's surrounded by 6 empty Teflon spacer tubes, then enveloped in a 4N copper shield and finished off with a final Teflon tape wrap terminated in a real-wood Ebony ring at the cuff of the RCA barrel. Sneaking the Japanese interconnect in place of my Zu Varials didn't have the desired effect. That was probably because the cable was virgin. So I'm piling on copper by the boat load elsewhere. In goes the Analysis Plus Oval 8 for speaker leads. This cable isn't as resolved as the Zu Cable Ibis (which actually plays louder at equivalent volume settings). But seeing that the Yamamoto has resolution to burn, I'm not too concerned at this stage. I'm attempting to redress the tonal imbalance. By acting like a mean bouncer, it prevents me from entering the inner sanctum. Ears ringing, lust at first sight is sorely tamed by the rather literal retorts of 'reality bites'. I want to love this amp but my ears are on fire and quickly turning toast.

Naturally, subtle dimensions of micro detail close down with the new speaker cables. However, the prior zippiness with its interludes of actual glare and brightness does mellow out enough to where listening is no longer painful (though the exciting aspects have gotten dumbed/damped down as well). A call to Brian disabuses me of an erroneous notion. There has been no prior play time at the Tokyo Tube Audio Fair after all. Zero. In the last minute, Yamamoto-San decided against rewiring a 220V unit for US voltage. He shipped a brand-new US voltage amp instead. Halleluja. My blood pressure instantly normalizes. Hope revives. I prepare myself for at least 100 hours of break-in. Just think of the coiled miles of wire in those sizeable transformers alone. So I'd observe whatever zigzag the sonics would likely undergo during that process as any real owner would.

On second thought, why would I assume that Brian had fought for the Yamamoto franchise -- and certainly not to gild his bank account -- only to hawk clearly compromised sonics and suffer plenty of product returns? That makes no sense at all. But impatience or carelessness with ancillaries has trapped many an audiophile before to pronounce premature and unfair judgment. Why not an impatient reviewer for a change? So I do what any self-respecting forward-thinking audio scribe would do. I replace almost every element of the reference system with review loaners. If I was going to be out of commission, I might as well go full hog and condemn my base line to hell. I consign myself to 2 weeks of zero
review activity while cables and various components are performing a simultaneous mass break-in on each other. One of these is the Music First Audio Passive Magnetic Preamp from England. At 8dB below unity gain from my 1V digital source feed, I'm way loud on my 101dB towers. This proves that the puny Yamamoto has an unusually high input sensitivity and thus, unexpected voltage gain for a micro-power amp. 0.5V for full output in fact, something Brian confirms when I ask for a hard figure. This means that even for sock 'em sessions, the +6dB step-up gain from the Stevens & Billington balanced trannies is sufficient to rock down the house. On 2 watts. Believe it!


Obligatory disclaimer: Buying a micro-power amp is like buying a Corvette. Don't complain to the dealer if you can't seat the entire brood or your nephew kills himself entering a corner at 110mph. You buy a Corvette, the dealer assumes you know what you're doing. If your speakers' bass alignment requires high damping factor; power per se; if your preamp's gain is insufficient; if your room is too big or your listening levels too high; don't fault the flea-juice amp. You're expected to do your home work. This is esoteric fringe stuff for sophisticates (but you don't need to be rich to play).


Disclaimer #2: When mated appropriately, this type of SET -- perhaps because it's ultra simple without endlessly paralleled output devices and mondo trannies; without global feedback; in pure Class A -- is lightning quick. It's a precision machine of superior magnification power into music's hidden recesses. That speed also means dynamics, with the macro range naturally limited by power. Smaller transformers (appropriate for the puny output power) tend to offer better high-frequency extension. Long story short, if the output tube of choice doesn't suffer innate response limitations, such SETs can be - er, ultra linear. In triode. Bass reach, power and definition are far more a function of appropriateness on part of the speaker than the amp. Think impedance plot, phase angles, damping factor and back EMF such as would skyrocket from multiple paralleled large woofers. Certain speakers, while copasetic everywhere else, will still present this type of SET with a combination of bass parameters that'll make for sub-optimal results. Again, not the amp's fault but yours. If you tie the knot properly, bass will be good not just for the genre but good, period.
Though not a traditional tube/high-eff wrinkle, the advent of the outboard subwoofer and the subsequent integration of powered bass sections into main speakers makes for the potentially ultimate solution in micro-power setlandia. By feeding the speakers' integral plate amps high-level from your valves, you assure tonal continuity. My Zu Cable Definitions are one such design. They relegate sub-40Hz mule labor to the onboard amp while everything about 40Hz is handled by your dainty bottles. Albert Von Schweikert's dB99 [right] is another such speaker. Its bass system runs off a 300-watt Class D so-called booster amp, a rather descriptive nomenclature that indicates high-level connection to work "in tandem" with your SET.


Such integrated semi-active speakers are theoretically preferable to outboard powered subwoofers. The speaker designer had full control over hand-over frequency as well as amplitude and phase compensation. You end up with the most seamless bass blend - and in stereo rather than mono. Avantgarde Acoustic's range of hornspeakers with active bass systems are another perfect candidate for today's consideration.


If bass augmentation rather than all-out infra bass is desired and your main speakers extend below 50Hz -- like The Second Rethm for example, a favorite of Stealth Audio cable guy Serguei Timachev, personal reference of reviewer Vade Forrester and perhaps the ultimate Lowther implementation -- a single inexpensive active sub could be all that's needed to add just a touch of foundation, weight and tone color without overloading a smaller room or vibrating the neighbor's intestines. Now you're looking for 30Hz sub reach and an adjustable subwoofer low-pass that allows for <50Hz settings. No need to go deep into hock here. Think single 8" or 10" in a sealed box. You want precision and tautness, not distortion, flab and boom.


For stand-alone infra bass, the 2 x 15" 100dB efficient Zu Cable Method sealed subwoofer is tailor-made to keep up with the inherent speed and jump factor of high-efficiency wide-bandwidth drivers and extends cleanly to 16Hz.

In the end, there are countless ways to play out your micro-power trump hand. But remember, you gotta play it, strategically and deliberately. Why to even bother with all the extra home work and hands-on experimentation this entails remains for the next page when this amplifier has been fully cooked. Right, the included power cord and a Ziploc bag with colored rubber rings to dress the Yamamoto interconnects. Incidentally, the enclosed page for those talks about an additional function for the rings besides cosmetics for routing purposes. They're said to damp the metal barrel. Another manifestation of purpose which permeates everything Yamamoto seems to touch, starting with the shipping box and packaging materials.


I've said it already but I'll say it again: This amp instills such pride of ownership, such obvious care on part of the maker pertaining to the most persnickety details you'll never see (unless you unscrew the bottom casing); and it is priced so unbelievably fairly considering that audio seems to again be in a bull market where anything goes as long as enough customers are willing to part with large enough wads of cash; that I'm all set to purchase the review loaner if its sonics come around and level out in the presence region band. Now that I know how virgin my loaner really is, I'm having high hopes indeed...