If you're talking about portable use, then you are looking at a higher-powered portable like an iPod or an amp to use the SR80's.
First of all, the SR80's are open so a lot of ambient sounds enter into your listening field... so your phones have to go slightly louder than a closed one.
The SR80's are listenable from a 5mw MD and an 8mw PCDP, but driving them at this level, you
are better off with a cheap Koss, Senn PX100 or something similar.
I'm glad that trying odd combinations with all the phones I've had pays off, and I can help people
