My Burson Conductor headphone amplifier USB Dac is connected to my iMac (27-inch Late 2009)
Processor 3.06 GHz Intel Core 2 Duo
Memory 8 GB
Running OS X Yosemite 10.10.2

I am running Sennheiser HD 800 Headphones.

The conductor is simply connected to my computer via USB port. The sound is incredible!