Buzzing depending on load

[Disorbia]

I recently built a new machine which i'm very happy with except I have 1 issue.
Im listening to music through a tube amp and it is connected to the rear 3.5mm audio port of the motherboard.
The audio coming out through the motherboard is very noisy, and after playing with it a bit I figured the noise source is the graphics card (maybe its fans) which is radiating a lot of buzzing to the audio components and conductors.
It doesn't matter which audio port I use (front or back) its still very noisy and the noise gets stronger as I increase the load of the PC.
Is it possible that Asus did a bad job at the audio part of the pcb? or it may be something else in my system.

Or my expectations from this motherboard are too high?.

The main specs are:
Asus Z170-A
Intel i5-6600K @ 4.4Ghz
GIGABYTE Radeon R9 390

Thanks!

[r4tch3t]

Is the sound coming through the headphones or from the card itself? Off is from the card it will be the inductors vibrating at various loads. You can take the card back for a replacement, they may want to verify it though.

If ours through the headphones then it's electrical noise of some kind. Easiest way to stop this would be an external amp with optical in.

[kasugatei]

If you connect headphones directly to the same port on your PC and there is no buzzing, it is ground loop. In that case you would have to either get something which will make galvanic isolation between PC and the amp (this will work for sure) or get external USB DAC (can still produce ground loop depending on the DAC design thus not solving the problem)