I have a gigabyte 770ta-ud3 and was wondering how i get the headphone port on my antec 300 to work. I know there were cables for HDA and Ac97 but i think i would have plugged those in if i knew where they went.
More aboutheadphone header
On your motherboard, next to where the rear audio jacks are, there is a green 9-pin header labeled "F_AUDIO". Just connect the HDA cable to it.
And make sure that you have loaded the chipset audio drivers.