I like this "Passion for Sound" guy, but I think he's a bit lost in this particular review. The main theme of the review was an imaginary (in my opinion) grainy treble. This is a bit unfair. Although I must admit that I didn't love Aune at first sight.
The reviewer focused rather on subjective matters, pushing into the background such important issues as the dynamics and power reserve of this amplifier, which are such an important element of every audio game.
In my opinion, the resolution of Aune's sound is due to its incredible dynamics and perfect linearity (the reviewer claims otherwise).
A perfect example is the Led Zeppelin song "The Song Remains the Same", which thanks to this hellish dynamics from the Aune S17 gets a new life, there are layers, there is drive... for example, with the Singxer SA-1 (which is very good by the way) this recording is almost flat.
When it comes to this treble, in my opinion Aune has a pro or rather audiophile character, it is never the hissing and ticking known from hi-fi devices. The decays have a definite momentum and power, but without much "tail".
It is more consistent with what we hear at concerts, and never with what comes out of, for example, average home hi-fi speakers.
Or maybe Aune is so transparent that he finally showed some grain of the reviewer's system, you never know....