I recently installed an Aorus Z370 Gaming WIFI Rev 1 motherboard with a 9600K. It has a sound blaster chip installed in the motherboard used for onboard audio. The motherboard has multiple outputs for a 5 channel configuration. I have my headphones plugged into the headphones channel and there is a noise/buzzing constantly when the machine is on, no matter if output is muted or not. If I move my headphones to the normal stereo out, the noise stops.
Is this a grounding or shielding error? I do not have every, single standoff screw installed, should I do that? Why does it only happen with the headphone output but not the speaker output?
I would contact vendor support for the motherboard. Aside from the audio issue, you should have the standoffs in for the system. That should not cause audio issues, but it's not a good idea to leave out support for the motherboard since it can flex and crack connections.