My Vsonic VSD3 sound same good as Audio-Technica ATH-IM70, and IM70 is almost in the same level as my Sony XBA-H3 or UE900 with my phones. But if you really want try most potential from the UE900 price point, you should use at least mid-fi DAP, for example FiiO X3II or X5II (or with External DAC+AMP). What you get from DAP/External DAC in comparison to phones is more detailed and bigger sound. But again, different from phones and DAP/External DAC would be personal experience, for someone noticeable, for someone not. However, with DAP/External DAC you get more noticeable difference in sound between UE900 and KC06A.