When I connect my mac and Aune with an optical cable, the sound becomes a lot harsher

Very clean sound with plenty of push to drive 250/300 ohm headphones

It is not cold, thin or harsh sounding, but also not warm or “gooey” like a tube amp

The sound is clear, neutral, smooth and full, with good soundstage and no noise or distortion

It's a lean and mean system with a really lively sound.

It possesses one of the cleanest dacs around and it provides good soundstage along with crystal clear neutral sound

and beyond, you are talking about small, varying degrees of good sound