You also have the problem where you do not want to hook the two negative speaker outputs together. You want a resistor between the negative speaker output and the common negative hookup on the headphone. I believe most amplifiers would balk at shorting the negative speakers outputs together.
Single ended headphones have individual hot connections for the left and right sides but share a common negative hookup. You don't want to try hooking that to your speaker outputs. You may get away with that on some amps but I don't think you want to fry anything.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
