What's the best portable DAC/AMP for Shure IEMs? I just recently got the SE846 and it worked okay on the Fiio E7K, but it broke unexpectedly. I bought the new HRT MicroStreamer, but it seems to have some problems where it pops or the left ear cuts out and I need to replug it. I can also hear a slight hissing noise. Does anybody have any recommendations? I mainly plug it into a Mac computer.