I can't comment on the 1st sound, but I have a Calypso with:
Rowland 201 monoblocks
Modded Sony 777
Linn LP12
Aerial 9 speakers
Evans "groove" phono stage
Kubala-Sosna Emotion IC's
JPS power cords
Acoustic Zen speaker cables
Shunyata conditioner
various tweaks and stands
LOVE the Calypso. I run balanced IC's to the amps (Rowlands like balanced) but all RCA's in from the Linn and Sony.
My room is 26 x 15 x 8, but that doesn't matter for the preamp.
I have not owned AR gear, but the match should be just fine. I ran the Calypso into some Bryston gear for a while and it was equally splendid.
I upgraded the tubes, just for fun, and of course different tubes make a different sound, but it was much more subtle than the same changes with other preamps I've owned (Rogue, Melos, Sonic Frontiers).
Anyway, you can't go wrong with the Calypso in my opinion.
Rich B