buzzing noise when TV is connected to PC

[bigpow]

I connected PC line out to TV line-in. Buzzing noise is apparent.
Any hint?

I think it's DC volt that I'm hearing.

Thx

 

[JustAnAverageGuy]

Little more specific?

Type of TV? Type of computer output?

 

[adeno]

If it's a buzzing noise, that's not DC.

I've experienced this before, it's called a ground loop problem. What you're actually hearing IIRC, is a 60Hz signal coming from your cable line. I'll spare the technical details, but try disconnecting the cable and see if the noise is still there. If not, then the problem is indeed a ground loop. You will need to buy a cable isolator and connect it to your cable.

I use the isolator in the following link and it's done well.
http://www.hollandelectronics.com/catalog/25.pdf

 

[bigpow]

Yes, I think it's ground loop.

Is that problem related to the cable TV signal or AC powering TV/PC?

How do I fix it?

Filter will remove the buzz, but the problem is still there, right?


Many thanks

 

[adeno]

The problem comes from the cable TV signal, so disconnecting the coaxial cable should stop it.

See if your local electronics store has some Cable Isolators in stock.. that should fix it. I've done this twice to two of my HTPCs and it's worked perfectly with the device I linked in my previous post.

The filter will just simply remove the 60 Hz buzzing sound that you hear. Of course, since it is inherent in the cable signals, this solution will not fix all the cables in the house.. you'll need an isolator for every PC-TV combination you've got.

 

[glennchan]

It might be that you are feeding your TV whites that are too white. Feed your TV a non-white screen to check if this is the case.

 

[manko]

Originally posted by: bigpow
I connected PC line out to TV line-in. Buzzing noise is apparent.
Any hint?

I think it's DC volt that I'm hearing.

Open your Control Panel:Volume Control and make sure your Microphone and Line-In are muted.

 

[thraxes]

Originally posted by: adeno
The problem comes from the cable TV signal, so disconnecting the coaxial cable should stop it.

See if your local electronics store has some Cable Isolators in stock.. that should fix it. I've done this twice to two of my HTPCs and it's worked perfectly with the device I linked in my previous post.

The filter will just simply remove the 60 Hz buzzing sound that you hear. Of course, since it is inherent in the cable signals, this solution will not fix all the cables in the house.. you'll need an isolator for every PC-TV combination you've got.

Bingo!! We have a winner!

I can indeed confirm that this is the most common problem when connecting a PC with a TV. I work part time a a studio technician at a large TV station and we have those problems pretty often.

 

[bigpow]

Isolator it is then.

How about using two 75-300 ohm balun back to back?
Would it do the job?

 

[Auric]

Another possible way of eliminating or significantly reducing the ground loop effect on the cheap is grounding the "cable TV" cable to the PC. I had a problem with this recently and ended up getting an isolator also. I listed a few of them in the thread at rage3d.