DAC options

I want to connect my iPad, and an USB pendrive to my Jolida JD801 amplifier, which digital to analog converter will be able to read the music in the pendrive? as I assume one that can process the signal from the iPad/iPhone is more simple to find.
any recommendation?
My budget is not a major problem as I am looking something in the $300 to 800 or more if it worth it
Juanin, I guess what you are looking for is a Music Streamer, with an integrated DAC on it. Google under Logitech Touch as an example.
Look no further then the New P S Audio Nu Wave dac.
It retail for $1k but underwood Wally sell it for $699
It is a outstanding dac uses very good Burr Brown dac, and does not use Any op amps just discreet components. Will compete with any thing out there up to $2k ,the. nad M-51 is the only think that betters it at $2k.