Word of warning for these, I've just had to send these back for the second time due to the incessant buzzing / whining in either or both ear cups.
Thankful for the Koss lifetime warranty, but I wish there could be a more permanent solution. Especially as I have to send them all the way back from UK to US, which takes a long time and is starting to add up in postage costs!
That being said, they're the best sounding pair of headphones I've ever owned and I was lucky enough to be able to get them in the EU sale for about £250. I've heard if you can get a Stax amp for these they'll really shine, but my budget wont allow that just yet!