Hello, I was looking for some input on using my iMac to produce audiophile sound through headphones. This is my first Mac so... I have a set of Shure SE310 headphones and I am considering a set of SE510's. $500 headphones wont make a differnce is the sound source is bad. I assume the sound card has a bunch to do with the sound quality. Is the original sound card good? I was thinking about purchasing a headphone amp such as the Total BitHead that uses a USB input from the Mac. Is this the right track? http://www.headphone.com/products/headphone-amps/the-mobile-line/headroom-total-bithead.php So basically what do I need to do or buy to get the best most accurate sound currently possible from my Mac through really good headphones?