[Ides]

I'm considering buying Sennheiser HD600's to use with my turntable and MacBook Pro and need a headphone amp to complete the system. I have a decent phono preamp for the turntable and a six year old but working HRT MusicStreamer II that I could use with my laptop (or alternatively get a headphone amp with digital input/DAC). Any suggestions? Open to buying used.

 

[PinkyPowers]

You might be able to find the Schiit Lyr 2 for $300, USED. That would be an excellent amp for the HD600.

Here's one on Head-Fi Classifieds near your price:
http://www.head-fi.org/t/822580/selling-my-schiit-lyr-2-price-drop

And one not so near your price:
http://www.head-fi.org/t/821405/schiit-lyr-2-with-lisst-tubes-20-hours-price-drop

 

[Ides]

Looks like that one only has one input.
 
Have been looking even more since I posted, and am discouraged there seem to be none in my price range that work for me. I have found a few that have multiple inputs but those don't have RCA jacks which I need for my turntable.

 

[PinkyPowers]

Most amps use RCA jacks, I can't imagine what you're looking at that doesn't.

For multiple inputs, you may be better off getting a switcher box to go with the amp, like this.

http://schiit.com/products/sys

 

[ProtegeManiac]

  Looks like that one only has one input.
 
Have been looking even more since I posted, and am discouraged there seem to be none in my price range that work for me. I have found a few that have multiple inputs but those don't have RCA jacks which I need for my turntable.

 
You can get one that has USB digital and RCA analogue. Ditch the HRT and hook up the Macbook via USB, then use the RCA for the TT.
http://www.matrix-digi.com/en/products/78/index.html#page4