If anyone can help with a suggestion or two, it would be greatly appreciated.

I've just hooked up a computer to my living room "theater" setup and have attempted to connect the PC to my Yamaha 5.1 surround sound amplifier. The PC has a Sound Blaster Audigy 2 sound card which supports up to 6.1 surround setups.

There are a number of connections on the card but I am using the three analog line out connections. The first drives the front left and front right, the second drives the two rear surrounds, and the third drives the center(s) and sub. My amp has RCA inputs for each of the 5 speakers and the sub that are for external surround processors. These bypass the amp's built in sound field processor and the sound card suggests that I use these. I made the connection based on the instructions from the sound card by getting 3 shielded 3.5mm to RCA stereo splitters from Rshack.

The problem is that there is a VERY annoying, low pitched hum that I can't get rid of. The amp doesn't do this when I use my DVD player or when I pump the sound from my cable box into it.

Any ideas? Thanks in advance.

Sounds like a grounding problem. Try to make sure all units are properly grounded to the same AC circuit. If your amplifier has a ground post, run a good sized wire from it to the chassis of you PC. But then, I had a similar problem once and the only way I could get rid of the hum was to lift the ground from the PC with a 3 prong to 2 prong adapter.

Grounding loops can be a devil to solve. IF that is what the problem is.

Check wiring- unplug each wire one by one until the hum goes away or see if the seating on the pc or the receiver is solid.

Thanks guys!

I haven't tried the grounding solution yet, but I'll definitely give it a go.

As for the plugs being seated, I've told them to sit down several times... O.K., bad joke. Actually I have done what you suggested. The hum begins immediately when any of the three plugs are inserted.

Then there is definitely a different level of ground between your puter and your amp.
Best bet would be to run a wire from amp chassis to puter chassis.

+1

There’s also another problem that I found a while back, which maybe causing you the same grief. When both the individual outs where used at the same time as the digital out (both selected in the SoundBlaster software) there was allot of noise present including 50-60 Hz hum.

DJ

Good news and bad news...

The bad news is that I'm not using the digital out at all...either in software or on the board itself. So that's not the cause in my case. But thanks DAZ for the reply.

The good news is that grounding did make some difference. It's not perfect, but it took a lot of the hum out. I'll keep fiddling and will report back results. Any additional input is still appreciated.

Thanks to all!

I had something similar with a Sound Blaster LIVE! Mine turned out to be a poor cable. I was running RCA to my REC. I checked all the connections but still had the hum. When I replaced the line with a slightly better cable the hum went away.

Some folks have had good luck with these as well. Not saying thats the best brand to use...but its convenient.
One of your local stereo shops should have what you need. If your pressed for cash, you might want to hunt the internet.

Here is a site that deals in ground loops. Its a fairly decent write up.