Leave ANY SS device on 24/7/365, unless you know you will be away for a few days, or there's a thunderstorm on it's way. A pure class A amp will draw some juice and throw some heat when quiescent, but any other class won't be an issue. You'll notice a major sonic difference(warming up) if you turn the power amp on and off. Give it a try, both ways(same music/volume levels), and report your findings. Of course: all that depends on how resolving the system is, and how critical/discerning a listener you are.
