HeadRoom Total BitHead Headphone Amp
You bought the nice headphones for your MP3 player or computer, but you're not hearing everything properly yet. Sure--it all seems fine, but you'll notice a big improvement in sound quality with a real (albeit miniature) power amp driving your tunes. Connects via audio cable to your MP3 player or via USB to your computer (bypassing your built-in sound card entirely). Needs four AAA batteries if not drawing power from your computer.