I just bought a pair of Sennheiser HD 598 headphones. (Don't critique that; I don't care.) I have an X-Fi Titanium sound card currently and a spare Xonar DGX. The X-Fi doesn't have a headphone amp on it so I'm wondering how I should connect the headphones. Would using the DGX's headphone amp make for a better experience than using the X-Fi with my Z506's headphone pass-through? Or is plugging it directly into the X-Fi best? Eventually I would like to get a proper DAC but for now these are my options.