Try the Xin Super Macro 3. I have used it with both the HD600s and the HD650s. I have the optional BB OPA627s installed on it and it is superb.
You might try a website called www.head-fi.com
It's a serious website for headphone enthusiasts - there are many writeups about headphone amps, headphones, cables, DACs, etc...
Cheers,
Dennis
You might try a website called www.head-fi.com
It's a serious website for headphone enthusiasts - there are many writeups about headphone amps, headphones, cables, DACs, etc...
Cheers,
Dennis