I have my PC connected to my stereo so I can play CDs and DVDs through real speakers, but lately I noticed an annoying hum coming through the speakers.  I don't hear it much when the music is actually playing, but when it's quiet, it's really irritating.  Does anybody know how I can get rid of that?  I'm using a basic cord that I got from Radio Shack that has stereo RCA plugs on one end to connect into my receiver, and a 1/8" (?) stereo plug on the other end that goes into the PC's headphone jack.  Can anybody tell what the problem is?
>:(

  Yup, I'd check/adjust volume first. If your using Windows there should be a speaker icon in the right side of your taskbar(bottom right of the desktop). Just left click it and a volume control should pop up. You really shouldn't go above 75% of the maximum.
  If that doesn't help, make sure you have the speakers plugged into the correct output. Some(many?) sound boards have an amplified output for non-powered speakers and a non-amplified output for powered speakers. Be sure to use the non amplified output.

  If that doesn't help, make sure you have the speakers plugged into the correct output. Some(many?) sound boards have an amplified output for non-powered speakers and a non-amplified output for powered speakers. Be sure to use the non amplified output.


This is exactly right.  Most normally, that buzz is when you plug a "line out" to an amplified signal.

Another problem can be what is called "sound floor".  Most low-end and built-in sound cards have a level of line noise that is more noticed when it is amplified.  I work as a DJ, and encounter this all the time when I hook up through the high-end equipment at most clubs.

The best way to counter both of your problems is probably to upgrade your sound card.  Very few "built in" cards have a non-amplified line out.  If you get something like a Turtle Beach Montego or Catalina, or a higher-end Creative Labs card ($100+ range) you will get a lower "noise floor", and also gain things like 5.1, 6.1, or 7.1 surround sound, and non-amplified line outs.

Personally, I recommend the Turtle Beach cards.  I have used them for over 5 years, and have always been very happy with their quality, and their cost.

http://www.turtlebeach.com/site/products/soundcards/

I'm pretty sure I get the same effect whether I use the speaker inputs on the front OR the back of the PC, so maybe they're both amplified.  But I'll try it again when I get home.  Funny thing is, I don't remember hearing the buzz before recently, and I've hooked it up that way on and off for at least a year.  I thought maybe I did something different this time, like use a different line input to the receiver or something.

The buzz is a lot less if I turn down the volume on the receiver and use the volume control in Windows instead, but I don't get much sound that way.  Anyway, I don't think I want to spend money on a soundcard right now.  And I sure don't want to mess with trying to install one.  But thanks for the suggestions everyone.