TBomb06, the first thing that comes to mind is a cold solder joint. I'd try reflowing stuff around the sensitive area, going as far as reflowing the whole board.
Today I finally got around to beginning this project. I had never soldered SMDs before so I started with assembling the DAC. That way if I broke or lost something I would order it with the parts for the amp.
Turns out it was a lot easier than I feared. With the fine tip of my iron I was able to solder the ICs pin by pin, which was a nice surprise. I expected the board to take a few days to assemble but I did it in a few hours. Quite a fun project, so far.
I haven't powered it yet since I washed it with flux cleaner. I'll wait for tomorrow to make sure everything is dry. Fingers crossed.
Crappy cellphone pictures:
Now, reading the BOM I see we are given the choice between a 12v rail and a 10v one. I figure the advantage of the 10 V is more current, but I can't really see the advantage of more voltage. On what factors should I make my decision?