If you want to disconnect your power for Home Theater devices, recommend you buy a Smart Power Strip. Many UPS (batteries) come with this built in as well.
Basically, you plug your primary device into the "Master" outlet on the strip. There are "switched" and "Always On" plugs to choose for the other devices.
Let's say you put the DVR/Cable box, TV, HT PC, BluRay player, PS/4 or whatever else you might use for TV entertainment on the "switched" outlets. You could then plug the AV Receiver into the "Master" outlet. Now, when you turn off the receiver, all power to the switched devices is turned off automatically. Keep your clock in the "Always on" plug, of course.
You could also make the AV Receiver always on, and use the TV as the master to switch the cable box, game systems, etc, on/off. That way you can listen to music and keep the video devices powered down.
Lots of ways to do this, and more than one smart strip lets you decide which devices depend on which other devices to be powered on.