Which Headphone Amp for Sennheiser 600?


I want to buy a used headphone amp to drive the 600, any suggestions?
bigboy
I'm using a Musical Fidelity X-Cans II on mine and it sounds great, just make sure that you upgrade the tubes.I used to only used them on my SF Line 2SE but a seperate amp really does make a difference.
But if you really want a great headphone amp check out the top of the line from Headroom.
I am also using the X-CANSv2 with my 600's. Can you explain to me about upgrading the tubes in the X-CANS?
Grado RA-1 with my Senn 600's, sounds terrific. I like the performance, simplicity, appearence, and the fact it runs off 9V batteries, one less thing to plug in.
I have a Wheatfield HA-2 for sale with a wide variety of upgrade tubes available. It's the top of the line tube amp that Headroom sells. Plenty of power for the HD600s (which I use too) and an extremely dynamic amp. If interested, contact me.