I have a DNA-1 which about 2 years ago suddenly became mono. I replaced the internal fuse and it blew right away (this is a good clue that something is seriously wrong). I then contacted Steve McCormack. I had the unit upgraded at the same time that it was repaired. The output transistors needed replacement. Cost for the repair was $120 and the turnaround time very reasonnable. That has been the only problem in 6 years of ownership. Good luck.
