Hi all, Im a newbie to this forum and need some advice on what amplifier I should buy for a newly purchased Sennheisers HD650 headphones. My source is a desktop PC with an onboard soundcard. I heard the HD650 sounds ok through a soundcard but obviously if you want the full potential you need a amp. What would you lot recommend to buy to power these to there full potential running through a PC? Budget is around 200-300. Also why do some people have a DAC and amp running these HD650's? What is a DAC?