I am trying to use an old amp (marantz pm47 - nominal 40 watts per channel into 8Ω) with a pair of speakers (Kef Coda 7 - nominal 10-70W at 6Ω). Every so often it clicks (the same like the power-up click) and it mutes the speakers. It recovers after an inconsistent amount of time. It doesn't happen just at very loud volume. I am feeding the amp through a jack to RCA cable from a tablet. Any suggestions of what could be the cause and possible solutions?
I bumped into this years ago when, as a kid, I though hey, the more speakers the better!! So I connected 3 or four sets of speakers in parallel to the little system. It would often 'click' off like you describe.
It boiled down the the ohm ratings of the amplifier and speakers being entirely mismatched.
Also, check to be sure there isn't a short in the speaker wires.
The 'click' you hear is the self-preservation mechanism of the amp that prevents DC current from reaching the speakers. See this other question...