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The sound in triode mode compared to pentode was certainly not night and day. Triode mode brought a bit more openness and air that made the sound a bit more natural. Pentode had a bit more dynamics with better bass impact. It should be more matter of taste than compromise between higher power and better sound. 300 watts should perfectly drive most speakers on the market. Going for an extra 100 watts should only benefit a few very difficult loads. In either mode the Orthos XS remained accurate and delicate. Here they remained slightly different versus what I experienced with other big valve amplifiers. They sounded truly effortless and far more civilized than a CAT JL2 or JL3 for example. Their huge delivery of raw power always was accompanied by both ease and delicacy, never brute force.

On Sarah Lenka's Hush [Emotive Records] the jazz club ambience was superbly reproduced and with utmost clarity. So were the incredible presence and vocal fragility of the young singer. Over my two Luxman M-800a the soundstage was wider and the sound more liquid. Ayon's midrange was perhaps not as gorgeous and warm but still more accurate than my Orpheus Three M. With my Japanese amps the sound had a kind of organic density not obtainable from the others. On naturalness I'd say that the Ayons delivered the most realism followed by the Luxman then Orpheus Labs. In fact the Orthos XS had the kind of SET sound that made textural subtlety quite incomparable to the others. Sarah Lenka’s voice had all the soft subtle detail that clued me to the notion of closeness to how the music was recorded whilst the Luxmans provided a bit more romance and forward projection. In the end the Orthos XS did not sound ethereal like other tube amps I tried on my Vivids but were more holographic and three-dimensional.

On Peer Gynt conducted by Paavo Järvi [Virgin Classics] the depth was impressive and the accuracy and speed of transients outstanding. The Orpheus Three M are truly very good at this but the Orthos XS stood a clear step above my Swiss amps, demonstrating an effortless nature which eludes these transistors. Treble purity and the resultant soundstage enveloped me in the musical event. Powerful, taut and deep bass suggested a real-life experience because of its amazing linearity. In any area of the bandwidth the Orthos XS sounded natural due to this rare alliance between absence of compression and presence of organic feel. The Orthos XS had me hear the initial attack in adequate proportion to the subsequent resonant fundamental and resultant harmonics.

Listening to Cantate Domino featuring the Oscar Motet Choir [Proprius] the Orthos delivered a pleasant and realistic rendering of this very natural analog recording captured with only two Pearl TC4 microphones and one Revox A77 open-reel recorder. Accurate localization of each voice, extension in the bottom end and sensation of depth all felt completely respected. The Ayons were top performers with recorded acoustics and a profusion of ambient detail. On each track of this audiophile recording and despite its age I was able to feel the air floating inside the church within a fluid organ rendition. Church pipe organs are definitely a meaningful indicator of hifi accuracy especially for speakers and amps. Most audio systems cannot reproduce the correct intensity of the whole bandwidth and the first two octaves often sound too recessed or uncontrollably loud but never right.

A very stable amplifier associated with accurately designed speakers should resize the organ to its normal scale and make it breathe softly. [Ahem – normal size relative to even Joël's dedicated room really remains a misnomer when dealing with a church organ. When is the last time you tried to get an organ in there? - Ed]. That’s where the Orthos XS seemed very much at ease, opening up a huge soundstage well outside the Vivid K1s.

Playing sophisticated but more compressed music such as Tears For Fears’ Elemental [Mercury] the Orthos XS did not slam as hard as as my solid-state contenders but nevertheless demonstrated great skill with pop and electronica. Listening to the last opus of Tears For Fears after Curt Smith's leave at insane levels, the Austrian amps still remained very clean and cast a large deep soundstage. Very often big tube amplifiers do not offer the required density to get involving with Pop and Rock but the Orthos XS did. That was no small feat. The new KT150 seemed to be particularly efficient with this musical genre. Its huge reserves of power allowed for an effortless reproduction of large dynamic swings.

Conclusion. The Orthos XS monoblocks put an end to the guesswork formerly inherent in large tube amplifiers whilst crossing new thresholds of sonic performance. The sheer quantity of detail, drive, space and emotion revealed in familiar recordings was nothing short of outstanding. Thanks to their huge precision-regulated power supplies these monaural amplifiers handle the most demanding loads with ease, ensuring consistency of performance under seemingly any condition. 400 watts of class A power result in impressive dynamic headroom and tight deep resounding bass. Ultra-short circuits and audiophile-grade components convey a bold vivid freshness. Like other previously mentioned Germanic heroes of legend, the new Orthos XS come close to truly vanishing with an effortless naturalness commonly reserved to low-powered single ended triodes. Conceived as a cost-no-object tour de force, this final iteration of the circuit still seems affordable in absolute terms once we contemplate its actual competitors in the market place. That’s why a reasonable price for this kind of beast allied to top design quality, apparent reliability and fabulous sonics call for a Blue Moon award bestowed by a solid-state lover who could very easily live with Ayon's very big tube amps.
Ayon Audio website