The very best compliment your toothless old single-ended triode hound could make here? He didn't suffer the irritating flee itch usually encountered when swapping out resident components for solid-state review loaners - or attending tradeshows all anxious to get back home in front of his chewed-up bone. Translation? While the Unison didn't exactly sound like my customary 30-watt AUDIOPAX monos, it also didn't telegraph the crude or more hooded deviations from the full-bodied sound I'm used to. Unlike so many silicon amplifiers, it didn't perform subtractive math on treble refinement or midrange realism, didn't flatten the stage dimensions. Naturally, high-power solid state nearly always does bass differently than low-power single-ended. The Unison was no exception. While the question of better rather than different is best left to personal tastes, I did not hear what (in my AUDIOPAX review) was secretly referred to as cyborg bass: Over-etched, overdamped dryness with an unrealistic amount of leading-edge sharpness. In other words, no transistor brutality in upright bass land, something certain Terminator and Matrix aficionados seem hell-bent insisting on even with normal music. The Coda Unison was a sand amp this lover of -- empty -- glass bottles could listen to for an indefinite period without feeling cheated.


Unlike for this rejoicing inner music lover, 'twas a bitter pill for our pen jockey though. How to succinctly describe an amp that signs its sonic John Hancock with invisible ink? Seeing how much I'd enjoyed the Bel Canto eVo2i to bestow one of our carefully reserved Blue Moon awards on it; and how the solid-state duo of BCD PRe1 and unbridged eVo 200.4 at the time proved a virtual clone of this direct competitor to today's contestant: Why not explore the Coda's overt lack of personality vis-à-vis this pre/power combo that would stand in for the long-since departed Class-T integrated to create context and evaluate the Unison's competitive edge?
But first, the promised comparison of high-versus-low Class A bias. Unexpectedly, whenever I switched back to the Unison even with my hornspeakers, the high-bias enhancements in tonal saturation, perceived fullness and presence were very similar to an A/B rigged by not fastidiously matching levels - the slightly louder one will sound slightly better; more fleshed out, with higher color intensities. Given that the stand-alone amp's gain structure was identical to the integrated, simply swapping speaker leads while not touching the volume setting guaranteed perfectly matched levels. Lo and behold, that's not exactly what it sounded like though. The ability to hear a bit deeper into the soundstage, to be more aware of the subdued tiny sounds that decoded its shape, height and reverb, was, while not drastic, as easy to pick out as preferring a speaker that plays 1dB louder. Inserting the nOrh SM6.9 into the chain drove this point home further - vocals and massed strings had more weight; more gold, less silver; more yellow light, less blue. In fact, this comparison reminded me of the AUDIOPAX TImbreLock adjustments. With its twin poles of lean/precise and voluptous/thick, the sliding bias allows calibration of just the right mix of attributes. The Stage 3.3 amp, though more powerful on paper, was harmonically slimmer than the integrated. While not threadbare by any stretch, it shaved off just enough harmonic density to move a belt hole or two closer to what Bridget Jones called the "American stick insect" in her diary.


One could also describe this minor reduction of focus or juiciness in terms of apparent listener seating. The leaner Class A/B presentation was just a mite more removed, more distanced, the hotter biased denser - as though timbre had moved closer while actual performer distance remained unchanged. Prospective owners requiring gallons of raw go juice shouldn't feel hesitant - these differences, while audible, didn't alter the overall flavor. Think of it just as two clockwise clicks on the intensity throttle; if you're a frank lover, hot rather than regular mustard. If power's no issue, go for the point-1 versions. For the same price, you obtain the kind of appreciable advances that, with digital front-ends for example, tend to cost quite the fortune once you've staked out the relative high-ground with something accomplished yet not silly money - say an Arcam FMJ23. It's similar also to upgrading a preamp - you get more body without losing low-level resolution. This suggests that a user-adjustable sliding bias feature on solid-state amplifiers -- as is commonplace with many tube amps -- could be an idea whose time has come?


While the Unison 3.1 ran merely warm to the touch, its higher idle current did make for a bit toastier operation than the 300-watt Stage 3.3 whose thermometer reading barely moved the lazy quicksilver. Even with the 88dB-or-so nOrhs, the Class A/AB integrated stoutly acted as a bona fide Class A amplifier and was a welcome break from the old model of the Nelson Pass Aleph-3 - its top plate could have fried eggs. Minnesota alert: The Coda will not double as space heater!
The unbridged eVo 200.4/Unison 3.1 comparo netted shockingly little qualitative differences, especially in the all-important midrange that had the purity of low-power SETs, albeit without that '3D holographic presence lock' where tubes still rule. Bass control (tight, articulate, "fast") on both pieces was phenomenal but the Coda piece -- notable only on the nOrhs -- actually served up slightly larger portions when it came time to dishing out ambient slam beats. Bridging the eVo for 360 watts equalized that advantage but was really outside a fair oranges to oranges juxtaposition. The only half-way substantial differences? Treble texture seemed of even finer weave with the Class-T amp. Moving back to my tube monos showed neither of the transistor amps capable of completely recreating their billowy top-end air, rendering things just a bit drier.


An area where both excelled? Micro-detail reconstruction of ambient recording environs, of particular note with all of the just-reviewed albums by m.a recordings that tend to take place in high-reverb monasteries and employ a simple pair of direct-to-Fostex-DVD spaced omnis.


From the very first percussive rustling on Será una Noche's brilliant La Segunda, the Unison overshadowed listening room geometry with that of the Argentinean Monasterio Gandara, lightning-quick reflections of Maguilevsky's recorder flashed and vanished like bat sonar, the slightly off-angle bow position on certain of Iannaccone's cello notes obvious as daylight, by exciting cavity resonance to a less sonorous extent. It's this type of subliminally encoded data which, when recovered, transforms sounds into manifesting not only in living space -- audible, hence visible -- but has breathing performers slip inside the notes, expand them three-dimensionally like worn clothing, possessed, animated, coaxed to be slighty off, imbued with character, shaped by momentary whimsey.


Lidia Borda's Latin vocals vibrate with surly directness when she gets intense. The Unison captured this liveliness, the slight underlying edge behind that emphasis, the minor thickening approaching raspiness in her throat on this peak, the sheer mass of air pressure delivered to the microphone diaphragms when she makes a lyrical point. Marcelo's hypnotic harmonica solo sliced the air like Samurai steel, clean and efficient, without ugliness, just high-speed transient timbre with little harmonic content, in sharp contrast to the simultaneous warm, woody, redolent bass clarinet. Passing all the usual tests -- full-bore female vocals, Anne-Sophie Mutter's violin doing Sarasate, Neeme Järvi conducting the Scottish National Orchestra for some symphonic Prokofieff -- the Coda-Continuum amplifier proved to be an extremely capable performer that never signalled 'electronics'. Its minimalist line stage centered on the BurrBrown attenuator chip even kept up when the eVo 200.4, rather than jacked into its pre-outs, was fed from Bel Canto's stunningly pure PRe6.

Verdict? Those familiar with the textural finesse of low-power SETs -- inherently transparent, fast, materially light without being unduly lit up by exaggerated trebles --will instantly relate to this high-power bipolar design that extends this quality as low as your speakers will go. With no trace of pancake flatness, the soundstage nearly comes alive before the first note is played, such is the ambient retrieval capability of the small air movements that make up even silence. Not as dense as the 47Lab Shigaraki Integrated or my thermionic monos, the harmonic envelope still remains far removed from early -- and diehard --complaints about solid-state thinness. In short and as said earlier, an amp that even a Px-25 fanatic could fully get behind, trading minor loss here for some gain there (most certainly in what speakers you can drive, and what kind of bass control to expect).


Coda: Marketing manager Mark Ward became the fact-checking recipient on the firm's behalf, of the ready-to-publish review you just read. His subsequent e-mails made me realize that he was quite happy about my unvarnished functional criticisms from the introductory page. He was clearly secure in his belief that the Unison was a sonically final and dialed-in component regardless of what I'd find. He also seemed to clearly know that it could benefit from a once-over detailing job to make it as competitive in the aesthetic and feature leagues as it already was on the actual sounding board. Perhaps he merely needed to collect some hard-hitting professional critique to get back at the engineers and jump-start this process?


As we shall see, this -- or something very similar -- seems to indeed have transpired. It makes this supposition more than just a pretty while self-important notion. Within a few weeks, 6moons is promised another unit whose silver face plate, Cardas terminals, reversible volume control readout and remote interface are said to address all issues raised. Once this dream boat drops anchor in our little desert hideaway, we'll give it the olde digital camera treatment and report back to you - on how Coda-Continuum implemented well-meaning feedback to further refine a high-power integrated amplifier that already deserves a straight A for sonics and build quality. Such responsiveness on Coda's part is highly admirable and unusual. It once again reiterates the responsibility reviewers should (shudderingly) shoulder. It also reminds us about the concomitant charge to wield this power in benign and carefully considered ways.

Manufacturer's website