Medion P6624 on Ubuntu 16.04 Xenial -- Ground loop audio issue?

After playing around with Windows 10 in various forms on the Medion P6624, I encountered an issue during one update that caused a blue screen loop. I couldn't resolve it quickly, so gave up and flipped to Ubuntu Xenial v16.04.

I really like it actually, and for most of my use it has everything I need.

I have discovered one thing though, that is again Medion P6624 related.

Put on some headphones, turn up the volume, and you'll hear a buzz that sounds a lot like a ground loop issue.

Not good.

If you touch the metal lining on the key pad buttons, it disappears like magic. So along with the BIOS issue that causes problems with Windows 8 and 10 installation and updating, it appears there are also grounding issues between the notebook motherboard and the analog audio out!

I'll have a think about how I can fix this, but at the moment, I'm happy with just reporting it here in case anybody else has a BUZZ when they plug some headphones in, and have sensitive enough hearing to detect it.