Hello: Building some cords - only want to cut the wires once, to connect my M13 to my Send & Return loop on my HD500X and I can't find anything that tells me for sure if the tip on the send is the left channel or right. Does anyone know for sure? Yes I can assume, or re-plug, but I'm the type that would like the correct info BEFORE I cut the wire and solder it to the plug. Thanks