You might want to try out a Blue Circle Thingee between your Mac and your Emm Labs DCC2. In my experience it works well between mine and a Bel Canto DAC2. It's a good sounding and very flexible unit. Here's a review .......
http://www.goodsound.com/equipment/blue_circle_usb_thingee.htm
http://www.goodsound.com/equipment/blue_circle_usb_thingee.htm