Motherboard 3.5 jack interference?

[Logicjunkie520]

so i just finished setting my shelves and desk up with a set of sony cs5 bookshelfs with a fosi audio amp.

Im using the 3.5mm on th back of the mother board for the audio out but if i have the volume knob on the amp i can hear a tick go in and out like some form of interference i know its either the cable or the pc since it goes away if i unplug it

what are some good 3.5mm to rca cables that are shielded and what can i do for the pc to eliminate the tick

it has a nzxt n7 b550 mobo

i want to know what i can do before i expand to have a subwoofer and rear audio in the room 

i also turned the treble up to make the sound clearer as its a higher end i do know the noise thats just white noise from turning it all up but im not worried about that part

it does not change with system volume