Athenas will work nicely, IMO. They're my favorites in that price range.
As for the Cayin, it's a great amp for what it is but you might consider the JVC RX-F10S. J&R has it for $250 now with free shipping, and IMO it's in an altogether different league than the Cayin. Tighter bass, better detail, clarity & definition on the high end, and still a wonderful tube-like midrange. Lots of posts on it in the digital forum at audiocircle, and I'm far from the only one who's owned or at least heard both amps and has this opinion.
http://www.jr.com/JRProductPage.process?Product=3978103
Gary
As for the Cayin, it's a great amp for what it is but you might consider the JVC RX-F10S. J&R has it for $250 now with free shipping, and IMO it's in an altogether different league than the Cayin. Tighter bass, better detail, clarity & definition on the high end, and still a wonderful tube-like midrange. Lots of posts on it in the digital forum at audiocircle, and I'm far from the only one who's owned or at least heard both amps and has this opinion.
http://www.jr.com/JRProductPage.process?Product=3978103
Gary