[BLACKSasquatch]

Hi, I'm kinda new here and I wanted to know if there was a portable dac+amp combo for my Sprint SGSII. I know they have a few for the iPhone 4 so I was wondering. my phone uses micro usb, I have the MTPCs and all my music is at least 320kbps (most is 900 or higher)

 

[PurpleAngel]

Your Sprint is able to transfer files thru USB, but most phones can not play files thru USB.
The Fiio E11 portable headphone amplifier can connect to the headphone jack of your phone.

 

[NZtechfreak]

As far as I'm aware the SII cannot do USB audio, only way would be if a custom kernel developer supported it (like they did for the Nook), but I haven't kept up with SII development having moved on a long time back.
 
S3/Note 2 can do USB audio, likely all Samsung flagships will from here on out, worth bearing in mind at upgrade time if you're wanting to use a USB DAC with your phone as a portable rig.