What tubes in the Granite 657 cd player?

What other cd players have you used and how did they compare?
I'm impressed with the perfomance of this player so far. I found a few posts that were all positive I recall, but not a lot so I'm interested in feedback from other owners.
While we wait for a Granite 657 owner to stroll in....how many have tubes in their cdp and what have you found that sounds good in them?