So... you want either one amp or the other to drive this pair of speakers, right?

The current levels involved in power amplifier outputs will require your amplifier choice to be made by a relay.

About the only major flaw I've run into with autosensing units comes from misunderstanding how all the parts work.

Let's say you have a pair of speakers in the ceiling, and you want them to sometimes run off of a house multiroom system, and sometimes you want them to run off the amplifier in the TV.

This has worked poorly when it was set up so that turning the TV on would switch the speakers to connect to the TV. You see, since the TV is not played all that loud, it wasn't very good at staying on, especially on a bedroom TV at night.

The same setup works GREAT, though, if you make the house system select which amp the speakers are connected to. The house amp signal will usually be larger than the TV amp signal, so it's way less likely for the house amp to drop out than for the TV amp to drop out.

Otherwise, Xantech might still have an IR-controlled relay, the CC12. (If you're controlling more than two things, the CC62 is an economical choice -- it has six relays.)