I was reading a thread on the benefits of external amplification and a question came into my mind. One person in a thread said that when he used a separate amp for his center channel, his main amp was "unloaded" and was better able to power the L & R mains. Is this true? Or does this simply mean the center channel amp within the receiver goes unused? Applying this to a pseudo EX set-up: Aside from the additional rear center channel, can the improvement of sound using a pseudo EX set-up be also due to the unloading of the main receiver from doing the surround amplification?