I just received a D70, Bluetooth version. So far, I've tested the USB and optical SPDIF inputs, works great!
However, I cannot see the D70 advertising itself via Bluetooth. I have tried my Linux PC, my Android 10 phone, and a Windows 7 laptop. None of those client devices see the D70 advertised.
I also have a Topping DX3Pro, which I was able to use via Bluetooth with all the mentioned devices. Am I missing something silly, or is there a chance I got a unit with a broken Bluetooth?
I hope you found the issue yet, but if not, I experienced the same thing and I solved it by giving it a factory reset, then after that, I unplugged it, left it for 20 seconds and them plugged it back in. I am by no means and expert, but it seems the caps need to be drained of power or something like that. Beware, if you change the DAC to Dac only mode, you’ll need to unplug and plug again. Hope this helps!