Is there a way I can test that the USB DAC is actually receiving a digital signal from the phone and doing the analog conversion rather than the phone using its own DAC and just sending an analog signal through to the external DAC? I'm not sure I can detect a difference using headphones on the phone or on the external DAC. Maybe it's a real good DAC on the phone or a poor DAC on the USB. But it would be nice to be certain that the analog conversion is happening on the external DAC when connected. Using a Fiio E18 portable DAC and Sony Xperia Z3 running Android 5.
