The setup I'm planning will have both a TV for normal viewing and a projector for occasional movies. However, the projector screen will not be on the same wall as the TV, but on the wall to the right. I know I will have to move the center speaker, but I would like to avoid moving the front and rear speakers much. Instead I'd like to find a way to essentially rotate the speaker outputs without going to the back of the amp to rewire.
I'm thinking about getting 2 A/B switches setup as follows:
Switch 1 (Input Front pair from amp) Output A Left - Front Left Right - Front Right Output B Left - Front Right Right - Rear Right
Switch 2 (Input Rear pair from amp) Output A Left - Rear Left Right - Rear Right Output B Left - Front Left Right - Rear Left
I think this would be ok as long as the amp is off when a switch is toggled (and the two switches would always need to be consistent). I'm just not sure it's very safe. Are there any other solutions? Or any suggestions to make this safer?
If there is any bleed through on the switches, you could damage the amplifier. If this is the only route you have, you would do better to put everything on one high quality switch that provides a dead contact in the center. This is going to require shopping at a good electrical supply house and doing some wiring your self. Tell them what you want to accomplish and they'll suggest the part you need. You'll probably be looking at an eight pole, triple throw switch. The null point (on - off - on) does remove some of the problems though.
Jan is right, keep in mind speaker selcetor switches are not designed to work in reverse.
Just because a switch is set to off, doesn't mean there is zero impedance or voltage backfeeding to the receiver.
Jan's switch solution is a good one, but most supplyhouses are going to look at you like you have utterly lost your mind when you ask for an eight pole triple throw switch...only a supply house that regularly handles industrial switchgears is even going to have heard of one, and they probably will have to order it.
Not to mention thats gonna be one expensive mother loving switch.
You might do better just buy another receiver and use a series of single pole 120v switches mounted in a box.
Yes, an eight pole, triple throw switch is not going to be easy to find. But I am willing to bet if you can find one it will be of sufficient quality (and cost). You might get away with two three pole, triple throw switches and use them as you had planned the two A-B boxes. The amplifier has to have a common ground (most do) to make this work as you will be sharing the third connection point between the ground of the channels. The most important part of the switch is the null that is provided by the unused set of contacts. This is still a switch that presents some margin of error and would not be my first choice unless I was the only person that would ever operate these switches. An unknowing twist of the knob on one switch and not the other and there will be an unpleasant aroma filling the room if you know what I mean and I hope you do. This will still require a heavy duty switch and should not be a Radio Shack item.
But, basically the advice your receiving is don't use the A-B boxes. The chance you will blow up your amp is too great. Unless of course, you are looking to blow it up so you can buy something new. In which case, A - B away!