\rHi Eric:
There is no on/off switch, it just goes to sleep when not in use, I believe you will want to disconnect from your device to make sure. I have done some research into external outdoor plugs which have on/off capability through an app. There are a number of choices. The speaker cables are 10 feet coming off the enclosure, I believe we recommend no longer than 30 feet away. That is an interesting question about two pairs on the one amp and a single pair for the other amplifier. I think you can add an inline volume control between the enclosure and the first pair of speakers. In case you had to adjust between the two amps.I would definitely recommend if you do connect two pairs that they are identical pairs. And if you do different pairs between the two amps that at least they are similar like a Patio speaker AP525 on one and an RX-550 Rock on the other.
TimL/6-3-2020\r