I too just bought an Arcam rDAC based on my dealer/friend's recommendation. My first DAC, so no comparisons.
After 72 hr., the (free) Tara Lab 200 cable sounded only slightly better than the TOSLINK; will re-test later. 'Puter probs at the moment, so my music server is not up. USB results then.
After 1 week, the lower bass of my Conway IIa's has increased volume & provides a solid backdrop (esp. with organ & drums). Notably, there was exceptional detail in mid/upper bass that I'd never noticed before in the material.
The high-end seemed tighter & not as "bright". The mid-range seemed more restrained. This also applied to female voices of which I prefer more fullness. Am concerned with "soundstage". It's not quite right, so I'll have to move speakers around.
Hopefully, as the unit continues to break in, improvements will extend up the frequency range & also to soundstage.
A better coax would prob help, but why bother. The USB is gonna do the heavy lifting.
I'm already starting research on a new power unit & mods.
Humbled to be in such fine company..............Ed, a newbie