Hello,
I can confirm that this USB DAC works with the BB1, which is useful to add an optical output.
Reiyin DA-02
The only thing I had to do was scroll to the bottom of the menu and turn on the headphone output.
I suggest that when a DAC is attached it become the default output.
After only a week I am impressed at how the BB1 'just works' with minimal fuss.
Brian