So I currently have the Beyerdynamic COP's and I was very interested in purchasing a portable amplifier to go along with them. Ideally, I would like to spend $200 or less on this amp, and it would need to be USB since I would be running it out of my MacBook Pro. Any ideas?

So I am considering getting the Sennheiser HD800, and I was wondering which amps/DAC's go best with it for under $1500 total. I've heard that the Burson Audio HA-160D is a very good combo, but I'm also wondering about amps like the Woo-Audio WA2 and Apex Arete. What are your thoughts on the...

I am currently debating between the Ultrasone Edition 8 or the Beyerdynamic T5p...which one overall has better sound quality coming off of an iPod or MacBook Pro?

I am looking for a pair of excellent portable over the ear headphones for use. I would like my iPod to be able to drive them sufficiently, and would also like minimum sound leakage. Thus far I have thought about the Beyerdynamic T5P or the Audio Technica W5000. And when I say portable, I mean...

I am considering buying the Audeze LCD-2's however they are very expensive. If I got them, I would only be able to spend $300 on a Desktop Amplifier/DAC. Which Desktop Amplifier/DAC do you think is best for the Audeze LCD-2's for under $300?