I have McIntosh C-45, that replaced Bryston SP-1.7. It is a much better preamp. I understand it's the same preamp, as highly regarded 2-channel C-46, with extra 4 channels.
After I having it for a while in my system, I can't really understand an argument,that way too many people here are ready to make, in favor of "purist" 2-channel preamp (and everything else 2-channel) vs. " oh, blasphemy" multichannel.
The only other multichannel "preamp" I have compared it with, was Linn Unidisk SC player, that does have a preamp section. McIntosh is a better preamp (in my system).