Hi! I agree with Tswhitsel the Classe amps work well with alot of pre-amps.
I have a Classe CA-301 running Thiel CS6 speakers and find the Joule Electra LA100 MKIII pre-amp to be a very good match.I also have a Sonic Frontiers SFL-2 pre-amp but prefer the Joule. The sonic frontiers has a bigger soundstage of the two but the Joule beats it at everything else in my opinion. The CA40O is reported to have a bigger sound than the 301, so the Joule and ca400 might just be magic!
Good Luck!
I have a Classe CA-301 running Thiel CS6 speakers and find the Joule Electra LA100 MKIII pre-amp to be a very good match.I also have a Sonic Frontiers SFL-2 pre-amp but prefer the Joule. The sonic frontiers has a bigger soundstage of the two but the Joule beats it at everything else in my opinion. The CA40O is reported to have a bigger sound than the 301, so the Joule and ca400 might just be magic!
Good Luck!