ear acute


Anybody can point me out whats the difference between mk1, 2, and the current mk3? Only know mk3 has the usb input...appreciate any comment and help..
Regards,
audioism
Thank you Rja.

I also wanted to ask if anybody has compared Ear acute with Naim cdx2?
I owned an EAR Acute once and liked it very much. Have no idea what version it was. Tube rolling recommended. They now offer a DAC as well.