As long as you don't hook any of them to a grounded connection you are fine. I have hooked ONE side to a speaker and grounded the other, it works fine you just lose half the volume power (which is why I did it, since it's used inside my office). FWIW, Pin 13 outputs a nice line-level audio output that isn't amplified. It has a slight DC bias, so put a capacitor in series with it. I use an Orion for a RR feed, works great.
Polk County, Iowa