I have a Bluesound player and have swapped back and forth from the internal DAC to an external Bryston BDA-2, also a Topping D30 pro and cannot discern any difference. For simplification I went back to the blue sound players internal DAC. I know a lot of people are sour on the Bluesound DAC, but for me it's just great.
In my humble opinion the preamp the DAC is plugged into makes a bigger difference in sound quality.
In my humble opinion the preamp the DAC is plugged into makes a bigger difference in sound quality.