If you have your audio going out to usb, I believe the audio chain is not involved, and the VUs get no signal to display...
Hmm, they should, indeed... Have you tried USB B in? I remember having read here (or was it on ASR?) that there are subtle differences between the 2 ports...
Not sure I follow you? There’s only one USB input which is a USB C port. The other two ports are OTG and USB out.
Ouch, you're right... sorry then, I must have been confused with the Z8. What do you use to play to the A6?
If they have volume control over the stream amplitude, then it could help having them output at 0dB (MAX), and you control the volume on the device.
Anything new that states usb-C input does not involve the VUs then, that I might have missed? Uh, the VUs are far from being for professional use, but they are still a big eye-candy; they not working on every input is kind of annoying...