I just received a set of Sennheiser HD 380 Pros and I'm wondering if I could benefit from a headphone amp when coupled with my Asus Xonar DX sound card. I've heard good things about some Fiio products, but I'm not sure what the results will be with my setup.
Another question... In the meantime without a headphone amp, when plugging directly into the Xonar DX, should I use the the Front Panel Headphone Output, or the Rear Speaker/Headphone output? Is there a difference in impedance with these two ports? I've read through the Xonar DX manual and couldn't find much detail on it.