I just tried switching the 2 sets of leads from the KVM, to ensure I didn't have a bad cable.
Results, no change.
There is a pop when I touch the Test Left; but the audio never comes through.
This message was posted on behalf of Intel Corporation
Thank you for joining the Intel® NUC community. I am sorry to hear you are having audio issues.
Have you checked if you are running all the appropriate drivers for your operating system? I just wanted to let you know that the support for Centos 7 is very limited, in fact the drivers available for this Intel® NUC model are intended for Windows® 10 which is the official supported operating system. We do know that a lot of users are successfully using Linux distro's on their units, and we would recommend checking the Linux forum for peer to peer assistance on this matter, see the community here: CentOS - Index page.
One more thing I would recommend regarding your configuration is the use of straight connections, KVM's are out of our scope since these are considered adapters that distort the correct connections between the components.
If you have more questions, please let us know.