Sorry for taking this slightly off topic.
"For me, I liked the sound coming from the Ayre CX-7e MP better than the sound coming from the MAC computer and the Ayre QB-9 DAC. "
When I got my QB-9, I compared it directly to my CX-7eMP (using rips in the QB-9 of the same CD played in the CX-7). I was careful to use the same interconnect on both units. In my system/my ears, they sounded *almost* indistinguishable. The QB-9 was, maybe, a tad smoother and musical. The CX-7 *might* have been just a touch more dynamic. But it was a close thing and I doubt I could have distinguished them blindfolded.
The CX-7 is MUCH easier to use: just plop in a silver disc and you're golden. Computer audio is a PITA with ripping, tagging, and backing up files. Plus, you can drive yourself crazy with the endless computer-side tweaks (luckily, the QB-9 seems pretty immune to most of this non-sense). But the big pay-off is being able to play hi-res files up to 24/192 (soon to be DSD files after the upcoming upgrade). The great majority of my favorite music is at CD resolution but I find myself gravitating to my >16/44 library. Most of those files just sound so good! I now listen to classical way more than I ever did, mostly because that genre dominates my highest resolution files.
YMMV.