The leave on / turn off argument has been debated many times on this forum with no solid resolution that I am aware of. I have a tube based DAC and the manufacurer specifically says to leave it on if you listen regularly. The argument for that is the on/off cycle decreases tube life. Solid state is a different argument I think but I know there are some folks that do leave their rig on unless they don't plan on listening for a few days. With regards to the normal operating temperature, check out this article. Scroll to the second paragraph in the "On the Bench" section. He measured and idle temp of 40* C (104* F) which seems to indicate that your unit is operating correctly. If you have concerns about decreasing the lifespan of the unit I would email or call Parasound, they are very responsive.
