I am trying to run one guitar through two heads simultaneously. Putting the guitar to the two heads is done. I need help with the cab. I have an old Marshall cab with a single input. Can I take the output of my Marshall head and the output of my modeling amp and connect them into this Y cable described below and then put the single input into the cab ??? Y Cables - Effects send/receive "splitter" cable Stereo/Insert Y cable, Belden Wire, Switchcraft connectors Part Number YS301-1 Male Stereo TRS 1/4" to two mono 1/4 connectors.