Have the same problem as Misios, but it's definetly not overheating problem (it worked great for 36 hours using asio and foobar). It's something with drivers for Windows DirectSound. (It can happen within 2 minutes from system restart.) For me the reason fwas youtube videos in browser. If I only use it as Foobar+asio and not as default sound device all is ok. But of course it's kinda dissapointing.
In all other things this DAC+amp is great. So warm and tough sound. Tried it with Takstar pro 80 and Beyerdynamics DT 770 Pro. Sounds nice. Haven't compared to DAC-19+ C2 yet, but will definetly do it in near future. Also tried DAC with big ones Electrovoice elx-115p - without a mixer it was not so good as headphones (it was too truthfull with a bad recordings and mixer was negotiating the difference between good recording and bad ones in a good way(tried with Allen & Heat zed 10fx) Actually with good recording it sounds outstanding (for example "City and Color - Somethimes" was so good that I thought that I'm actually on a one scene with an artist)
And while I was writting this post it failed again but this time during track swithing in foobar+asio drivers.