I have a DacMagic Plus in my headphone rig but I am a PC guy.
I've tried USB (with the Cambridge Audio USB 2.0 driver) and coax. I prefer the USB but there's not a massive difference. I am using the Audio Advisor Pangea brand USB cable. Don't have the optical option from my PC.
Going balanced out from the DacMagic to a Burson HA-160 headphone amp. I have the HD-650, not HD600, and find good synergy in this system.
I've tried USB (with the Cambridge Audio USB 2.0 driver) and coax. I prefer the USB but there's not a massive difference. I am using the Audio Advisor Pangea brand USB cable. Don't have the optical option from my PC.
Going balanced out from the DacMagic to a Burson HA-160 headphone amp. I have the HD-650, not HD600, and find good synergy in this system.