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Joël Chevassus
Financial interests:
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Source: Esoteric K-03, Esoteric G-02 [on loan], Lumin, Apple iMac Lion OSX/Audirvana, Squeezebox Touch + Welborne Labs PSU, Audio GD Ref 5, Trends UD-10.1, MacBook Lion OSX with HiFace USB-S/PDIF bridge
Amp/Preamp: Rogue Audio Hera II, SPL Volume2, Orpheus Lab Three M, Trends TA-10.2, Luxman M-800a, Luxman C-800f
Speakers: Vivid Audio K1, Lawrence Audio Violin [on loan]
Cables: Skywire Audio 2020 digital cable, Naturelle Audio interconnects Live 8 MK2, Grimm Audio TPM interconnects, Audioquest K2 speaker cables, High Fidelity Cables TC1 –E speakers and interconnects
ower Cords: Audio Art Power 1 SE, Furutech
Stands & room: Audio Tools stand, Microsorber insulation, PYT Panels.
Review Components Retail: €23.500/pr

Weightlifting Round #1 – Ayon's KT150 Orthos XS. This review is the starting point for what you might call my curious weightlifting exercise. My next few reviews will focus on some of the most powerful commercially available monaural amps. Today's Ayon Orthos XS will be closely followed by Karan's most powerful KAM 2000, then Chord's SPM-6000. These will get compared to my own more modestly powered Orpheus and Luxman amplifiers. Despite the fact that ultra demanding loads have become quite rare in the current high-end speaker market, manufacturers still offer a few big amps with massive reserves of current and power. The relationship between power and sound quality is obviously not implicit. Dinosaurial amp eaters like Apogee Scintilla or Infinity Kappa speakers seem like a musty old story today. That makes a waste of money and crazy electrical consumption out of yesteryear's amps designed to drive them.

Yet brutish power remains a prerequisite for very ambitious speakers from average to low sensitivity to avoid overload and clipping. If your amp has insufficient power to match the logarithmic demands of SPL increases (each 10dB increase in acoustic loudness, say from 90 to 100dB, requires 10 x as much electrical power), the top and bottom of the waveforms representing the audio signal are clipped off to generate speaker-eating distortion. The next step leads the amplifier to activate its protection circuits to remove the signal portions causing the overload to generate further distortion. Another option are high-sensitivity speakers and low-power amps. Quite often this choice represents a thornier path to the audio heavens considering the degradation in tonal accuracy when such speakers are asked to play loud. There's also harshness and complete loss of off-axis performance as the weak points of horn-loaded designs.

Rest assured though that my intentions here are not as underhanded apologist for low-sensitivity speakers and high-powered amplifiers. Audio is made up of many options and choices. Synergy between the various components in your system remains key. My considerations only aim to highlight the interest one might nowadays have to acquire such massively potent monaural amps in the first place.

Small rooms and neighbors tend to limit our interest in them. But when somebody means to reproduce real-life acoustic sound levels in a sizable room without neighbourly considerations or big horns, big power requirements are mandatory. Here loudness should not be considered a kind of audio madness since clean undistorted loud sound often does not even sound that loud. In fact with most home playback small amounts of distortion are caused by lack of dynamic headroom. This distortion feeds into the 'loud' perception in a domestic setting. To remove those distortions and increase dynamic headroom now leads us to more powerful amplifiers. In the scheme of high fidelity, the last barrier to realism is having enough power to approximate real-life loudness levels. That is the central topic of my weightlifting series. Coming back now to Ayon’s new crown jewel, founder Gerhard Hirt has released an ambitious third version of the Orthos's first iteration with three possible sets of pentodes: KT88, KT120 and the new KT150. Released by the 6550’s father the Tung Sol label, the latter is an upgrade of the previous KT120 supposed to deliver enormous power, i.e. 35 to 40 watts per tube with utmost refinement and transparency. 400 watt of pure class A power from classic push-pull KT valves seems crazy for civilized watts and was previously reserved for a few OTL designs and the most powerful of Manley’s realizations. Yet that's also what Ayon's Orthos XS is about.