Amp Testing vs. speaker safety

I have a pair of B&W matrix 804's that have the biwire posts on the back. I want to a/b test a new amp in my setup with my old amp. the speaker posts have spade and banana plug connections. Presently the spade connections are to the prospective new amp. I would like to also run banana plugs to my old amp. I would then just switch the amp input (from my main outs on my pre-amp) RCA plugs from one amp to the other (of course turning off power to any amp before pulling out RCA input plugs) to test them. Would this proposed setup hurt my speakers, since only one amp would be live at any one time via the RCA input wires, although both amps would be connected by speaker wire? Also any potential harm to the amps with this setup. I will do nothing till I hear from my fellow audiogoners.
I do not recommend doing this. Keep in mind that the output impedance of most SS amps is well under 1 ohm. Given that your speakers are probably at least 4 ohms nominally, there would be less resistance feeding back into the amp than going into the speaker. As such, you would literally be ramming juice from one amp right back into the other amp that was not in use. NOT a good thing.

The only way to do something like this is to hook up a speaker switch box or manually swap speaker cables. If it were me, i'd go with swapping speaker cables. This keeps the variables to a minimum from amp to amp and they are set up as you would normally use them. I know it is a hassle to have to do that, but i know of no other way to do it safely. Sean
Thanks Sean, just trying to avoid the hassle but I am more concerned with the safety of the equipment.