I use my portapro with a cmoy amp I build with my sony walkman mp3 player . they sound great for the money -lrb- a little bassy but you can que it down -rrb- . I like that Koss get it right and have not change a thing in many year !! very comfortable for long listening . not a real pretty headphone set but they do the job well . quality seem to be good . I think with a little care they will last for year . I like they & I use they everyday .