We have had some issues with the DAX0 dac where the cs4398 chip has burned. We have been unable to confirm exactly what has been the cause when this has happened, but we believe it is related to static electricity. We have stopped selling the dac for a while while investigating, and we have come up with a ESD static electricity protection that we believe might help avoid the problem.
The diodes should be soldered close to the connectors (RCA). We have a few of the dxco left in stock. It is recommended to install the diodes, however these are not include these in the kit.
The dac discussed here: http://www.diyaudio.com/forums/digital-line-level/192353-hifimediy-direct-out-cs4398-dac.html
The DAC from Hifimediy is designed around the idea of putting all the effort on the digital and D/A conversion side.