For $45, you can also try Sony's D-25s discman. They may still be available on eBay through a place called Silicon Salvage.
Read the full review of this stellar player here:
http://www.head-fi.org/forums/showth...?threadid=4834
Although I do not have the 580s, this player is said to be able to power them without an amp, and I believe it. The thing is louder -- and cleaner -- than any other CD player i've heard, portable or otherwise.
The line out is said to be very good on this, also, so you can always upgrade and buy an amp later on, which is what i will probably do.
Good luck!