It's not advisable to allow a possible common connection point between two amplifiers. It can be done but requires some care. Why do you want to do this?
Thanks for your quick respond. Because I have a receiver for home theater now, but it's not for karaoke and I also want to set up karaoke system. If able to do that then I'll buy a karaoke amplifier to set it up.
You stated that REQUIRES SOME CARE, can you be specified about REQUIRES SOME CARE? Thanks in advance.
You can never allow the two amplifiers to see each other while powered up. Place "Parts Express" in a search engine and give them a call for the appropriate switch.