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In a deliberate series of 300B amplifier evaluations to educate myself on the subject, this review is the fourth installment. The Woo Audio Model 5 was a conventional 6SN7, dual-mono 5U4G valve-rectified design. The Yamamoto A-09S runs the high-gain C3m pentode drivers. The Trafomatic Experience Reference uses interstage transformer coupling, parallel output tubes and twin valve rectifiers. As described, Emillé's KM-300SE employs the 6350 dual-triode driver. That was manufactured in the 1950s by (or branded as) GE, Marconi, Raytheon, RCA and Sylvania. In 2008, it appears in contemporary gear by Joule Electra, Shindo, VTL and others.

Earlier research into the importance of driver tube selection was appended to the Yamamoto A-09S review. Naturally, it's just as relevant to the KM-300SE or any other SET with demanding output tubes. For more on the subject, click here. For a 'who's who' of current 300B suppliers, click here (this link includes a factory tour to KR Audio). In the context of my A-0-9S experiments, I had determined that the Full Music, Shuguang WE clone and current-gen Western Electric 300B share a vintage aesthetic. By comparison, the Czech valves of EAT, EML and JJ are modernized to offer wider bandwidth and more dynamics. Some refer to these versions -- the XLS and 320 in particular -- as 300Bs on steroids. Emillé's stock complement is the Full Music. The surcharge option is for Western Electrics. Add the outright recommendation against EML and KR tubes. Does Emillé's sonic ethos at least for this machine belong squarely in the vintage sector?

To answer that while generating the necessary impressions and comparisons, I relied again on a hifi chain of Esoteric UX-1 into Yamamoto's YDA-01 D/A converter with 3V output, into ModWright's DM 36.5 line stage. Following the dual-chassis American valve preamp were either the Emillé, Yamamoto or First Watt F5 amplifiers. The Nelson Pass transistor amp's ultra-low harmonic distortion and stupendous resolution would keep tube man honest. And because they're the most resolved, widest bandwidth speakers I presently own; and because their ruler-flat 6-ohm impedance below 1kHz makes them ideal for single-ended valve amps even without feedback; I leashed up Franck Tchang's mighty ASI Tango R. Since the Emillé doesn't require a preceding preamp, I ran it directly off the Yamamoto D/A converter after assuring that theory was correct - inserting a redundant gain stage through an external preamp was inferior. That acted like a gelatin thickener.


For context, no single-ended tube amp I own or have heard in my home approaches the noise floor and low-level resolution of the F5. The simplest test to determine that is playing something non-complex at low volumes, on albums with rich ambience. Compared to the F5 and to varying subtle degrees, all the tube amps inject some cotton candy fluff between the notes. Inter-note space isn't completely empty. Hence it's not as illuminated by harmonic auras. It doesn't fully become the transitional medium of decays. It is taken up by something already which generates an impression of density, warmth and soft focus. When present to higher degrees, those qualities mute the energy, veil overtone activity and reduce immediacy as though the music took place farther away. A recent Nelson Pass article on Distortion & Negative Feedback might point at intermodulation distortion from higher levels of low-order THD.

Let's talk tone color. One must distinguish between outer and inner color. The former is laid on. As such, it's applied. The latter is released, pre-existing and thus, natural. But the inner color can only materialize when not overlaid by outer color. With the F5 as yardstick, one has to grant its transistors the natural color. The valve amps apply minor alterations. One sure-fire indicator are the uppermost harmonics on an expertly recorded triangle. With nearly perfect 200kHz square wave chops, this particular transistor amp demonstrates superior treble phase, hence more unlimited overtone elucidation. This includes the harmonic signatures of all instruments and singers of course. A triangle's intensity simply makes it most obvious. The valves step down that ephemeral brilliance even if only a tad. Once keyed in, you perceive it as a very fine freshness whose diminishment inserts a degree of flatness or compaction. It's less filigreed, less breathy.

Tube devotees won't like to admit that a very simple, expertly honed transistor amp might not only be more honest to the signal (many of us confess as much while holding tightly to the belief that tubes own greater emotional conviction) but that this honesty can lead to greater truth of timbre and from there to greater beauty of timbre. The toughest test, again, is the one at low volumes. You either hear inside instrumental timbres or you remain somewhat on the surface. To enter the inner game of instrumental color at subdued SPLs becomes the test. Then the F5's stripping-away action of 'stuff' isn't loss of substance. It's the removal of fine dross which bares what's underneath. But this is a valve amp review. Let's return to regular programming. Extreme value seekers are simply reminded. Do the math on power, low-impedance stability, price, maintenance and sonic sophistication before buying into assumptions.
As it turns out, Emillé has some reason to champion the vintage tubes. Contrary to Yamamoto's circuit, theirs is more nubile and elastic with the Western
Electric and TJ and somewhat stiffer and drier with the XLS variants. It's academic to speculate whether Yamamoto's ultra-gain C3m pentode has superior control over those Czechs. For bias, the EML 300B XLS dropped in without any adjustments but their height required removal of the Perspex cover. The EATs too plugged in without screwdriver turns but fit underneath the Acrylic. These Slovak valves in fact were a terrific alternative to the Western Electrics by adding some upper-end extension energy and blackness in the bass. In the wrong system, I could envision a tad of glassiness intruding into expectations of 'classic' valve sound but in mine, I appreciated the more expansive overtones and wirier timing. In fact, the Euro Audio Team bottles became my favorites. They played for the solid duration.

Thus fitted, the distinctions between the KM-300SE and A-09S were more minor than what separates these machines from the Woo Audio whose 6SN7s, I suspect, are responsible for a degree of sluggishness by comparison. Of the three, the Yamamoto is the leanest and 'fastest'. It's convenient to invoke a pentode aroma knowing about the C3m. Perhaps that's indeed what it is. Sonically, it's closer to the incisiveness of a modern Emission Labs 45. Rather than golden, it'd be a bluish-silver hue, albeit not in color but as action. If the Yamamoto A-08S 45 SET made up one polarity and the Woo Audio Model 5 the other, the A-09S would sit closest to its stable mate, the Emillé with EATs next to the A-09S and thus a bit farther removed from the A-08S. With the Full Musics as delivered, the Emillé moves a bit farther still and hence, closer to the lazier Woo Audio - but there's still more separating the Woo from the Emillé than there is between the Emillé and the Yamamoto regardless of power tubes.

In modern vs. vintage terms, the Emillé is a modern implementation of vintage values. It stays clear of the slower, darker, somewhat cloying romanticism that has given 300B amps a nostalgic reputation. The truth serum of the First Watt amp confirmed that. At their particular levels of refinement, parts choices and circuit maturity, these amps are closer than you might think. There's ultimately more visibility into the farthest stage depth with the F5 yet lateral fullness is greater over the Emillé. What's between the notes is more informed with the transistors. The notes themselves are fleshier with the tubes. Invoke octave doubling from 2nd-order harmonics perhaps.


The transistors portray more silence and space between the performers, the tubes interweave more. Taken to the extreme, the first presentation would lose cohesiveness, the second become a mosh pit. But these amps are in balance. It renders talk of extremes useful only by rendering the essences more pronounced. Because of the more unraveled treble, I consider the transistors sweeter - as long as the recording isn't aggressively ragged of course. The in-between valve action creates more subjective warmth. It's important to distinguish between warmth and sweetness. They're not synonyms. As successful super tweeter experiments show, more extension in the treble seems to equal better phase behavior. That creates more inherent sweetness, hence sugar, not spice.


Bass grip and tunefulness with the Emillé, over a copasetic though truly fullrange load as the Tango, really wasn't compromised. While it's popular to correlate damping factor with bass quality, a very famous designer of solid-state amps is on record as never having discovered a consistent correlation between the two. The ultra-low non-complex THD from the F5 mostly comes to the fore in this context with complex material. Then separation is superior. For extremes again, think acrylics vs. watercolor. Loussier's Mozart Piano Concertos with 12-string orchestra and Jazz trio did not yet constitute undue complexity. To really appreciate the separation aspect, I had to attend church and cue up Mozart's Requiem. Massed mixed chorus over against a complex symphonic fugue had the F5 at an advantage if your listening preference favored ultimate visibility. That didn't mean the Emillé's lines ran together into a blotty ink spot. The participant perspective simply stepped further into the farfield for greater blending.

For a brief detour into single-ended 6C33S bottles with 6dB of applied feedback just because they were next on the menu, Ancient Audio's Single Six monos emphasize greater textural liquidity, vaster space and more redolent bass. Their treble extension is nearly the equal of the F5, i.e. superior to any 300B amp and tube in my arsenal. While feedback is a contentious subject particularly with SETists, it's not the boogie man when properly applied. This takes nothing away from the no-feedback 300B sector. It's mentioned as a reminder only. Buy with your ears. Compare a lot. Leave presumptions on greater purity to the theorists, tales of queens and kings of tubes to the story tellers. Trust your own reactions and be happy.
Back on track. While the 6922/6350 gain structure was not as stout as the combo of ModWright's 12dB circuit and Yamamoto's buxom C3m (the latter is truly packed with amplification factor), standard listening levels in the above space had me at 12:00 - 1:00 on the Emillé's stepped attenuator. Transformer hum on my 230V line was zero, speaker hiss over the Tangos extremely minor. To conclude, adjectives like elastic, mellow, relaxed, spacious, colorful and connected all fit the Emillé. This is a superior 300B integrated that's put together exceptionally well. Its attractive form factor takes up substantial space and weight is equally massive. A dedicated amp stand will probably be the preferred support.


Emillé is a player who just recently set eyes on the West in earnest. But they're clearly not a new player and this product's maturity speaks loudly to that. For those who'd regard Yamamoto's competing A-09S as too modern for a 300B specimen -- and that amp will require a separate preamp to stretch your purse -- and traditional 6SN7-driven variants as too yesteryear, Emillé Labs' KM-300SE is a terrific mid-place alternative. I see that Roy Gregory of HiFi+ came to a similarly solid conclusion on the company's KI-40L. If patience is a virtue and good things take time to get right, then Emillé has certainly spent their time well. While I doubt that the KM-300SE turns a page on circuit inventiveness, it's a solid implementation of traditional valve design made over just enough to appeal to today's audiences while not sacrificing certain values of a slower, more reflective past. And to gild this lily further for proper closure, the pride of ownership factor with this machine is truly through the roof. This really is one gorgeous piece of fine industrial design.
Quality of packing: Extreme.
Reusability of packing: Multiple times.
Ease of unpacking/repacking: Due to weight, not exactly 1-2-3.
Condition of component received: Perfect.
Completeness of delivery: Gloves, bias adjustment screw driver, full-line full-color lit.
Quality of owner's manual: Good.
Ease of assembly: None required. Tubes are preinstalled. Replacement requires removal of Perspex cover.
Website comments: Attractive but a bit tight-lipped on circuit details.
Human interactions: Congenial.
Pricing: Leverages Asian labor advantage for truly upscale results. For what's offered, squarely value-oriented.
Final comments & suggestions: None.
Emillé Labs website