Nothing! Just a bit of humour. This was a kludge to use an AK240 as a source for an amp. The purpose of the TRS is to get the ground connection, which the balanced out doesn't have. It isn't necessary though as no signal passes through the ground in a balanced connection. It is only used for connecting the shield (or connecting the ground between two devices, but that is another matter altogether).
6/27/14 at 10:31pm