This is the standard one socket, two plugs affair. It simply separates the bias and drive voltages so that you can use any amp to drive any headphone given that you have some way to access the original bias supply. Let's say you want to drive a normal bias Sigma from a 717 and have a SRD-6 handy or that you want to use the ESP950 off a Stax amp, yet use the Koss bias supply. The one for CanJam is so that the owner of a normal bias Sigma can experience it off the BHSE.