I ended up going with an external DAC to my Outlaw. I picked up a Grant Fidelity TubeDAC-09 (new model is TubeDac-11) which is a Tube/SS hybrid DAC/Headphone Amp for under $400. I've compared this DAC to friends units which cost over $1200, and most agree the combo with my Outlaw, Heresy IIIs and Paradigm Servo 15 blows their way more expensive systems out of the water!

I use an optical mini-Toslink cable from either my iMac or AirPort express to deliver the tunes through the DAC and into the Outlaw... I'd go that route, I tried may methods w/ the USB, Y-Cables, etc. and it just never had that right sound. Don't get me wrong, I LOVE my 2150, but an external DAC is always better than an internal.