I also have had the DA005 for several years. The problem may be with your files and not the DAC.
I did have popping sounds on my DSD files, but only those that I had ripped from SACDs.
It's a while ago and I don't remember the details of the fix, but after doing some research, I recall that I had to re-rip all of them using a procedure that set a particular bit. And the problem was no more.

