audio "hum" when playing vcd

[sgracer]

I get a low hum when playing a vcd or avi on the tv. Output from the soundcard to rca jacks on vcr produces the hum. I bought a new vcr thinking maybe the single audio input jack was causing it, but the dual input does the same thing. I have an older JVC tv with audio/video jacks in the back and when connected there it works fine. This happens on 3 different vcr's, 2 different tv's, and different computers. Any suggestions greatly appreciated.
Thanks,
Win98se
Asus A7V
1.2@1.33 tbird
Maxtor 45g
Matrox G400 d/h
256m crucial
PCI 128 soundcard
Second sys:
Win98se
MSI K7T Pro2a
Duron 700@892
Maxtor 30g
Matrox G450 d/h
384m pc150
cheap soundcard

[WMike]

I'm a little confused by your question.

Is the hum when playing from your computer directly to the TV? Or is it on capturing for processing to VCD?

You might try a different sound card. If it's captures, I find that a certain amount of noise is inherent in analog captures. Some are worse than others depending on the source material. When it a problem, I demux and run it through noise reduction in CoolEdit and then remux it.

Good luck
Mike

<font size=-1>[ This Message was edited by: WMike on 2001-07-18 21:51:26 ]</font>

[sgracer]

I thought it was fairly clear. The hum is from computer to vcr. not capturing or processing. As I stated, 2 different sound cards, different computers, 3 different vcr's. Very strange indeed. Seems like it has something to do with going into the vcr, because if I input it straight into my older jvc tv jacks, no hum.
Thanks

[zzyzzx]

I think you have a ground loop. I plug my VCR into the same power strip that my computer is using and don't have a hum. When I leave my VCR across the room and string a long wire to the computer I get a hum and have to use an audio transformer to get rid of the audio hum.

[patrickm]

yup, it's a ground loop all right. some other things you might want to try are to keep your audio cables away from long parallel runs next to power (AC) cables. another trick if it can be done discretely in your room is to use an extension cord to the far-away power strip, so that both strips are actually plugged into the same outlet.

the problem is that the ground voltage may not be the same on both outlets in your room. even though they're physically close, they can be electrically very distant. usually whatever's on the same breaker is equally well grounded, so if there's another nearby outlet sharing a breaker with the computer, use it. the cable signal coming from the wall can also be a problem if it has a different ground potential than the outlet. you can get an isolator for this at radio shack, or buy a surge protector strip with a cable pass-through.