Thx KP大大, the case and Power supply are very good. Cheap and excellent quality .
I am still running in the dac with some burning disc by th e use of some square wave. Up to now, it is much better than my Creative sound blaster live! Really worth to try!
Feeling that square wave is very powerful, now I can feel elite 840 headphone connected to DAC are much better than before...(I have not used burning disc to run that 840 before)