Don't believe technicians at retail stores - they're just salesmen

I've tried to connect my PC's soundcard to my Yamaha A/V receiver before and I kept getting this irritating humming sound in the background. So instead of trying to fix it, I just got my computer a basic Logitech 2.1 speaker system. Through the sound that comes from the speakers were fine for basic internet telephony or system sounds, I find it lacking for music and games.

One of the reasons I bought a Yamaha receiver and JBL 7.1 Surround Speakers was to enjoy music, thus it really bummed me out to find out that I can't get rid of the humming. At first I thought the problem was with the cables I used (I used a basic minijack to RCA cables) but when I tried plugging the cable to the iPod, it didn't belch out the hums, just the tunes.

I thought of many ways that I can bring the music from the computer to the A/V receiver like getting a D-link Medialounge or Buffalo Tech's Linktheater. (PC World gave Buffalo Tech Linktheater the thumbs up between the two.) But the thought of spending more than 200 bucks for this is kind of daunting.

When I went to Circuit City early this afternoon, the guy who assisted me said that the problem is my soundcard (I have a Creative Soundblaster Live! 24-bit). He said that the technology used in that particular soundcard is more than a decade old, etchetera, etchetera. He told me to get the Creative Audigy soundcard (which would have costed me $199.99).

Stupid tech person.

When I got home, I fired up Mozilla and googled "sound card humming receiver" then the solution came up. The problem was not with either the soundcard nor the cable nor the A/V receiver but a thing called earth loop. Earth loop happens mostly when you connect a myriad of components to the receiver with different grounding. To make a long story short, I disconnected all the components from the receiver and just left the PC connection - and surprise! No humming! Then, I connected the DVD player and the cable box. It is when I connected the cable box that the humming returned. Thus, I have isolated the problem.

For more information about earth loop and humming, visit http://www.jaycar.com.au/images_uploaded/humloop.pdf.

Now, I just have to buy a $16 cable earth loop isolator (from eBay) to fix the problem. Saved me a couple of hundred bucks! :)