Humming question

[trailsprinter]

New here with a question. I just ran a VGA cable, with an accompanying audio cable, from my computer, under the floor to my tv. However, when trying to watch streaming video or Netflix streamed movies, I get a loud and annoying humming sound as if I'm getting interference from another source. Could simply passing these cables through the metal heating ducts or near the under-floor heater be affecting transmission? Any ideas, suggestions would be appreciated!

 

[ljcox]

Two possibilities come to mind.

It could be a earth loop. Is the TV ground connected to earth via the power cable?

Or it could be induction from the VGA cable. The VGA cable carries the vertical sync signal which is 50 Hz in some countries 60 Hz in others.

If this signal is induced into the audio cable, it will sound like a buzz or a hum.

Are you able to separate the two cables by at least a metre?

If not, you will have to use a 2 wire screened cable.

To do this you will need an unbalanced to balanced converter at the sending end and a balanced to unbalanced converter or at the receiving end.

The converters could be either good quality audio transformers or differential amplifiers.

One amp would be designed to have an unbalanced input & a balanced output and the other vice versa.

 

[shrtrnd]

Yep, like ljcox said, sure sounds like AC hum induced on your cables.
Try to get your cable away from power cables. Sometimes motors in electrical heaters, or flourescent lamps on the same power leg (plugged into the same power source), can cause it. It helps if you buy good quality shielded input cables too.