There are times that I want to do some reconfiguration or testing of my system and I want to have a mono channel. Right now I am comparing two mono speaker systems. I want everything to go to the one mono speaker so I can listen to it and then I want everything to go to the other mono speaker so I can listen to it. I will then decide which system I like the best and then build and use my choice for each of my front channels. Is there any way to sum the channels by switching, or is the best that I can do is to connect the left and right channel through a "Y" adapter and switch to the two channel Stereo mode?