This is a great thread and one of the best discussions... So I figured hopefully you may be able to help:
I have the Polk PSW10 and I want to use the speaker inputs for my GB Pro, and use the RCA line in for my home stereo (subwoofer out). Can I do this safely without needing to unhook one (the RCA line in) to use the other? Can I use both devices at the same time (unlikely but just from a device safety point of view)