I have an Asus Zenbook Pro UX501VW running Windows 10 and Ubuntu 16.04 LTS on dual boot. Whenever I have headphones plugged in, there is a high pitch white noise that comes through. This noise is not there for Windows 10. I've tried disabling Intel power save and muting the mic input through system settings and alsamixer. Even if I disable all system sound the noise is still there.
System info: 4.6.0-040600-generic x86_64 GNU/Linux HDA-Intel - HDA Intel PCH HDA Intel PCH at 0xdd428000 irq 137