Over the years, Accustic Arts have constantly refined their symmetrical PCB layouts. Optimized shorter signal paths led to layout changes, better parts, upgraded capacitors but also a reduction of certain filter banks for the input stage, all in the pursuit of a musical result that would be free of typical transistor artifacts. Factor in luxurious power supplies and one entertains justified cause that the yardstick for sonic excellence has been moved up appreciably and beyond just typical marketing claims. After pressing the carefully chromed power buttons, these power amps checked in for duty with a fat relay click. A few seconds passed whilst the circuits stabilized and other relays opened the gates. This process was visualized by two LEDs moving from red to blue – and not of the optic nerve-rattling type which haunted older Krells. All my signals hit the Mono II amps via my matching Tube Preamp II Mk2. Needless to say, I was most expectant to welcome such a family gathering in my own four walls.

To kick off, I couldn’t possibly resist cueing up Volume I of Accustic Art’s own CD production Uncompressed World. This sampler of select performers was mastered extremely carefully and with maximized dynamic range. From the first beat, the diaphragms of my Acapella La Campanella floorstanders surrendered themselves into the grip of these muscular drivers. I had no reason to question the claimed damping factor of 600 into 4Ω. The attacks of Michael Frey’s concert grand on Feathers and Flames had the type of unassailable solidity which simply eludes smaller amps. The entire stereo panorama was perfectly sorted and unbelievably stable as though cast of a mould. And that across the entire audible bandwidth. Common claims for extra authority gained by using big monos seemed well earned.

One of my fixed references to assess the tonal accuracy of review loaners has been the CD version of the legendary Mercury long-play record SR-90175. Howard Hanson and the Eastman Rochester Orchestra demonstrate the sound of classical acoustic instruments solo and in orchestral interplay. This album enforces very realistic impressions. My carefully practiced protocol went quickly out the window however when the Mono II showed perfect mastery over the timbre discipline. This came off so assured and self-deprecatingly that I had the tacit sense of listening to this familiar disc not with amps but through a kind of acoustic microscope. The strings evidence lovely woodiness but perhaps a bit too much so. Equally obvious? Whilst the brasses of this orchestra thunder with bravura, they miss the perfect intonation of bigger orchestras. Where I’d assigned the Accustic Arts Tube Preamp II the label of ultra-professional mastering tool well beyond just working flawlessly, the same qualities seemed to apply to the amps and not to miserly degrees.

It seemed child’s play for them to sort out complex timbres with great precision. When in Mozart’s Sinfonia Concertante (KV 320d) the solo violin effortlessly separates itself from the viola or in Pergolesi’s Stabat Mater the alto remains distinct from the soprano or counter tenor, it not only shapes our listening experience but points at the exactitude whereby amplifiers can differentiate between overlaid often very similar sounds.