Hmmm, looks to me like Mikeyfresh has a CMB version of the M8. That means he's got the HD598 plugged in single ended. For balanced, he would be using both the front ports.
That silver thing would then be an adaptor for a 1/4 inch to a 3.5mm.
Edited by NZheadcase - 3/29/14 at 9:15pm