Sorry, cannot break away from Class A when done properly. I've owned several Sugden pieces and now an ATC SCA 2 preamp, also Class A. My reasons; immediacy of attack and dynamics, With few exceptions, everything else is slow and smears. Once you've experienced the energy and liveliness of Class A, most do not go backwards. The music is on top of you, slamming. Even orchestras benefit as individual sections become cohesive.
Not for everyone. It is not lush and romantic and poor recordings need not apply as they will be ruthlessly revealed, rendered perhaps unlistenable. The price paid.
Best success with your search. BTW a Sugden A21SE is killer. Cheers