I've tried to search on this topic, but doing so has yielded a fragmented impression of the issue. Apologies if this has been covered in depth somewhere, I did spend time researching but wasn't able to come up with a full answer. Plus, my experience with headphone amps is nonexistent. Basically I need to definitively confirm whether it is possible to directly connect a phone with a micro-USB port to a portable DAC/amp. Now, I have a Cowon S9 that is capable of driving any of my headphones satisfactorily. However, I haven't been using my S9 much because my phone (Samsung Galaxy S) is so much more convenient. Not only does it have 3 times more space (16 to 48 gb), but the superior music interface (player and management, via PowerAmp) and LastFM connectivity are desirable features lacking on the S9. Additionally, it's nice to know if I'm getting a call or message while listening to music and I can directly access new music via MOG or LastFM. OK, so all that said, there is a problem. A big problem. Not only is the sound from the Samsung drastically inferior, but the amp is underpowered for anything other than IEMs or other very efficient headphones. This leaves me trying to come up with some way to retain the overall functionality of the phone while beefing up its sound quality. I know I can port directly from the headphone jack into an amp, but amping an amp from an amp isn't ideal. I don't just want louder, I want better too. So, is it possible to connect through micro-USB to an amp? If it is, is there any product that already does this and if so, is it any good? Big thanks in advance for your thoughts!