What is the best preamp for Carver monoblock tube amps?


I have a great preamp in BAT Rex2 tube preamp. I am considering getting a Carver tube amp such as used Cherry 180 or the newer 350. Rex2 is an excellent preamp, but I don't know how well it will match with a Carver. I am using Soundlabs e-static speakers. What preamp do you recommend? 
chungjh
Which model of Carver? Do you know the input impedance?

Other than being able to drive the input impedance, the correct answer is along the lines of 'the preamp that you like the best'.
Get the order placed for the Carver amps, may take a few weeks if not in stock on the shelf.

 Get the preamp a tune up is all.
amazing preamp!