Demetrios, if you're talking about hearing a "click" when you did that with the 3808, whatever the noise was, it wasn't any amp turning off. There's only one amplifier in a receiver and it outputs through multiple channels of output transistors, which act like valves in sending the required amount of power to each connected speaker. When there's no speaker connected to a particular output channel, the amplifier, or even that particular channel, doesn't shut off entirely, but runs at a low "idle".
