They are powering their receiver from the external USB source! Seems weird to me. First, the DAC shows up in Windows device manager when it is turned off and unplugged from the power source. Second, device manager reports that the DAC requires 100mA. If, magically, the DAC starts using internal power when powered on, then Windows would have kicked it out and re-enumerated as a different device that requires 0mA. That doesn't happen.Are the Schiit DACs powering their USB receiver using USB VBUS power or do they just not work if the VBUS power is not there? It's a HUGE difference.
My two other DAC's are reported as requiring 0mA by device manager. They disappear from Windows when turned off. I don't know if they work or not when the VBUS power is not there but it is obvious that their USB receivers are powered internally.
I don't understand why Schiit decided to power their USB receivers by uncontrolled external power sources. I doubt they saved much by doing this. Maybe someone can comment on this.
As an inconvenience, now I have to not only flip the on/off switch but also to unplug the USB cable when I want to disconnect the DAC.