I justed noticed that you have a RPI4. Since it uses Linux you can probably fix your Metrum Jade DC using the command prompt and unmute it. You just need to login to the dac using the terminal. Either connect a monitor to the HDMI port or use Putty command on windows to login to the RPI4. If you have a macbook, then you can use the terminal command.
We can try using alsactl or alsamixer command to unmute your dac. Message me once you have logged in using terminal putty or directly using a monitor connected to the RPI4 hdmi port. You just need to connect your metrum jade to the RPI4 using the usb cable.
