"Ignition sense" = switched 12v, right? So, if a special wire gets power when the "CD changer" is selected, and that's hooked up to the switched 12v, then the empeg will only have power when the CD changer is selected. So, switching between empeg and another source will cut power to the empeg. Right?

Seems detrimental to the empeg to cut power, especially if you're just flipping to the radio to hear the traffic for a few minutes, then flipping back to the empeg. I have my source switcher set to always give empeg the power but yank power to the low end Alpine headunit which I use for radio and CD. In order to switch to the Alpine, I have to put the empeg in standby, which effectively pauses it, which is the goal if the above question. I wonder if that would work.