The 650's are unbelievable headphones. They are my preferred cans for "listening in the dark." It would to you well to invest in a headamp with those. As mentioned above, you can find yourself pushing the headphone output of your receiver awfully hard trying to make the 650's sing. Plus with a headamp you can run an iPod or PCDP or even a computer audio output through the amp to your headphones. None of those devices can do much with the 650's alone (or any 300 ohm cans for that matter).

"That's some catch, that Catch-22." "It's the best there is." M22ti VP150 EP350 QS8 M3Ti