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The Esoteric I-03 was one of those components which cause me concentration issues. I had a tough time extricating individual sonic traits analytically. "Nothing is missing, nothing attracts attention or disturbs" …was my spontaneous first reaction… "what else to say?" It’s of course very praiseworthy when a machine leads one directly to unselfconscious listening rather than subliminal references against an internal sound check list. But for a reviewer chasing clear personality traits, it’s actually more of a pain.
Dual-mono preamplification boards separated by steel barrier
So let’s start by calling the Esoteric an all’rounder rather than eccentric. This means maturity and balance without any aural bling or kinks. The same goes for tonal balance. Except here I wouldn’t go as far as calling it dead neutral since minor tendencies remain. To cross things off the list, I’ll begin in the bassment. For an amp of its sticker and kind this band conforms with expectations of power and reach. Bass is substantial, extended and neither bone dry nor buttery soft. Semi sec seems most appropriate. Unlike certain amps like the Gryphon Atilla, bass here doesn’t attract attention. This merits asking why. The Dane’s upper bass has a small emphasis which renders the Esoteric the more neutral by comparison in this area. This also means that the Atilla’s particular punch and fun factor don’t translate fully to the Japanese. The low bass of the Esoteric is finer and what’s perceived as better will depend on the listener.

Way down low the Esoteric is alive and twitching but gnarly records also make clear that more remains possible versus my usual combo of Octave tube preamp and Electrocompaniet monos. ‘More’ refers less to sheer quantity (though that factored a bit) but mostly to stability and articulation. Take the very very unusual woodwind fare of extreme sax player Colin Stetson—check out this Youtube video for a taste—on New History Warfare Vol. 2, Judges. On the number "All the Days I’ve Missed You" the infrasonic blubber of the French horns had firmer consistency with my pre/power duo and the inner structure of those noises was keener. Whether that’s any necessity is a different matter of course and that combo costs 30% more too. That it puts out more foundation energy is not entirely surprising.

One channel's class D output stage
Though more potent in the mid and upper bass, the Gryphon’s low bass was actually a tad lighter than the Esoteric’s. These descriptions are graduated hues and nothing earthshaking. In matters of infrasonics I’d rate the Esoteric as falling between the Dane and my German/Norwegian combo. Even so the Esoteric doesn’t produce ‘impressive’ bass like a big cruiser boat's bow wave. The lower registers simply act as seamless extension of the midband. And the midband is where the I-03 gets specific. But first the treble.

Here the same impressions/descriptions of the bass factor – flawless continuation of the vocal band without diva-esque attention grabs. I heard neither harshness, dirt nor extra sparks. Some amps draw out (or create?) more scintillating air particularly around brass and woodwinds. Here the Gryphon was cut from the same cloth. Neither amp directs the listener to pay specific attention to the upper frequencies. They simply exist and if in doubt register more on the milder side.
960VA EI core power transformer
The Esoteric goes on the charm offensive with the midrange. Here Tori Amos’ "Blood Roses" became perfect example particularly vis-à-vis my separates. Those handle this band decidely different. My initial quickie assessment was that the I-03 was warmer, the combo fresher. The cembalo string attacks were harder, more incisive, direct and steely over the duo; fleshier, fuller and softer with the integrated. This applied to the voice too. It seemed 3° to 4°C warmer than usual. This was accompanied by somewhat larger scale as though the voice had grown to occupy more space whilst outlines were somewhat less tacit or defined. I wouldn’t go as far as invoke a bath of golden light the Esoteric dips everything into but a core tendency toward bronze rather than silver is applicable – a very fetching nearly elegant hue that’s decidedly not the coldly analytical blue-white fluorescent lighting of strip malls.