Stereo speakers whistling

Hello!

I'm new to this posting thing, so please forgive me if I do something wrong. I am trying to help my son with his stereo, but have no electronic knowledge whatsoever.

He was excited to receive a Samsung MX-F830B for Christmas, but when he plugged anything into it (USB, headphones, etc.), the speakers made a very high-pitched whistling noise if the system was 'on' but the speakers weren't being used. The company allowed us to exchange it (thinking it was a defective unit), but the new one is doing the same thing. I should add that he plays his XBOX 360 on an monitor and is using the stereo for the sound.

I suggested that he just unplug anything he wasn't using, but he explained that he could hear the whistling from the speakers during the quiet moments of game play even while wearing headphones.

We even tried setting it up in the dining room (just the stereo) to see if spreading the components out would alleviate the problem, but we could still hear the noise when he plugged anything into it.

He also tried using the Toroidal Ferrite core on the power cable, but that didn't change anything.

This is supposed to be a great stereo (I couldn't find one bad review), but I don't think we happened to get to defective units. And I don't think I should have to bring a brand new stereo to a repair center and pay them to fix it (Samsung's suggestion).

Any suggestions would be greatly appreciated -Thanks for your time in advance!

I get the question your asking, but I have to ask,

Why use a stereo to begin with? couldn't you just get a mixamp and use the headphones that way?

@gamersmom1995: That does sound like you're getting a ground loop buzz. You said you've already tried a ferrite core cable, but have you tried plugging it into an extension cable or a surge protector. I have found that can sometimes get rid of strange ground loop noise.

For $350 you get much better sound anyway.