I want to output uncompressed multi channel audio from my Windows 10 PC to my AV amplifier over HDMI.

I have it working, I've got my amp connected via HDMI using the integrated Intel GPU's HDMI port. I also have a separate AMD Vega 64 as my main GPU.

That all works, I get uncompressed multi channel audio showing up on the amp.

However that also means that the PC is extending a desktop to that HDMI output, if I plugged a display into the output of the amp I'd see a Windows desktop.

What I'd like to do is just send audio over that HDMI connection and not extend the desktop there. If I do this the sound device for that HDMI connection disappears, understandably.

I've tried forcing that sound device to be enabled again, with devcon, but it has no effect. In fact once I've stopped extending the desktop to that output the only way the sound device is enabled again is by rebooting.

Does anyone know if it possible to output audio over this HDMI connection without extending the desktop there as well ?