Saint, I dug up my old listening notes from the a-b-a test I did when I sold my old CD-5 vs the buyer's Audio Aero Prestige -
"The buyer was using an Audio Aero Prestige player and we a-b-a tested it on the same music & the differences were certainly clear to me; the AA was more rolled off in comparison, the dac section was less detailed and accurate & the midrange was bloated. I also felt it had a 'sheen', like a veil clouding the music. The AA certainly sounded warm, though I felt that quality was compensating for omissions elsewhere. In comparison, the CD-5 had better weighted bass & extension, the above-mentioned veil was lifted, sound came from a dead quiet background & you then felt like the band were in the room playing for you. The buyer also noticed the improved detail and accuracy of the dac, whilst his wife noticed the above-mentioned veil being lifted, though on first impression said she preferred that quality in the AA."
...the end result? The buyer kept the Ayon and sold the AA.
I haven't heard the AA Capitole Mk2, but the Prestige was AA's previous top model. AA players do certainly sound organic in the way that Avalon speakers do, but ultimately I found the Ayon more satisfying. For synergy, i'd be cautious matching the CD-5s to your Bryston 6B SST. As Doggiehowser mentioned earlier, because the Ayon is a valve preamp & has zero NFB, it needs to be matched with an amp with high input impedance >47kOhms. The Bryston's input impedance is 50kOhms balanced & 20kOhms unbalanced, therefore if you decide on the Ayon, i'd run it in balanced mode, otherwise you'll get hum (read: bad). I use a Boulder 1060 which has an input impedance of 100k ohms (balanced) and 50k ohms (unbalanced) which is benign to even the weakest tube preamp.
Overall, if you want a more laid back player, i'd go for the AA, but if you want a more dynamic, vivid and 3d sound, i'd go for the Ayon (especially if you want to use it as preamp). Btw, for the CD-5s I recommend upgrading the tubes to 6H30P-DR's if you want to get even better resolution/dynamics, or cryo-treated EH Gold Pins if you're want a warm, lush sound. I also recommend upgrading the factory Burr Brown OPA627AP op amps. The OPA627AP's were about the best op amps 20 years ago, but are only midrange op amps today. I had my AE swap them out for Burson Single HD discrete op amps which were a nice upgrade. The Bursons sound more open like a stream, added sound stage width, improved bass & sounds more analogue.
Hope that helps,
MG