INTERFERENCE NOISE FROM MY SPEAKERS

[raffirp]

Hello,
I just build a media center PC
motherboard: Asus P7H55M Pro
with intel I3 550 CPU
i connected it to my sound system and i am hearing a distortion noise from my speakers.
what i did as diagnostics
-removed the board from the case
-added a seperate sound card
-added a seperate video card
still no luck i am always getting that distortion noise i even sent back the motherboard to replace still the same if anyone could help i would really appreciate it thanks

 

[Outlander_04]

have you tried another set of speakers?

 

[raffirp]

have you tried another set of speakers?

IT IS CONNECTED TO MY HOME THEATER SOUND SYSTEM HARMAN/KARDON RECEIVER WITH A HEADPHONE JACK TO RCA(EVEN REPLACED THE WIRE STILL THE SAME THING).
WHEN I CONNECT THE SAME JACK TO MY IPHONE THERE IS NO INTERFERENCE NOISE.
I AM WONDERING IF IT'S THE MODEL OF THE MOTHERBOARD I EVEN REPLACED THE MOTHERBOARD WITH THE SAME MODEL AND STILL THE SAME THING.
I WILL CHANGE THE MOTHERBOARD TO INTEL AND SEE IF IT WILL SOLVE THE ISSUE