I currently have an Apogee Duet DAC/headphone amp and I just purchased the Denon D2000s. Anybody have any experience with these 2 together? Is a separate headphone amp necessary? From what i've heard, the Duet's headphone amp is decent and preferably should only be used for cans that are easy to drive. I know the Duet's headphone out impedance is 30 ohms and the D2000s are 25 ohm phones. I've read that the Denons are relatively easy to drive (in terms of volume) but a good amp will improve the sound overall. The only headphones I have owned were the Sony MDR-7506s and they sounded good out of the Duet, very transparent and clean. Funds are kind of tight right now so i'd rather not invest in an amp, at least for now...just wondering if i'm fine for the time being. Any thoughts/opinions would be appreciated.