[mythtv-users] Hum on analog audio to TV

William william_munson at comcast.net
Tue Oct 21 22:26:44 UTC 2008


James Crow wrote:
> I have two Myth systems currently running. Both are connected by analog
> audio to RCA inputs on the TVs. My master BE/FE works great. 720P and
> analog stereo. My secondary FE (no BE on this box) is having an audio
> issue. It is connected to the TV at 480P component with analog sound.
> Whenever the Myth box is turned on there is an audible buzz from the TV
> speakers. I have tried switching from the built audio to an external USB
> audio device and the symptoms persist. Does anyone have any
> recommendation of things I can try to fix this?
>
> Thanks,
> James
>
>   

Several other people have mentioned ground loops and they are on the 
right track but are offering the wrong solution. If you can go digital, 
do so and you will be surprised how good it sounds. If you must use 
analog audio then you may want to buy or build a isolation audio cable. 
There is a good page about how to make one here

http://www.epanorama.net/documents/groundloop/audio_isolator_building.html

Its simple enough that most people can handle making their own if you 
have the tools. I did not research commercial versions but I am sure 
they exist. Another option would be a UPS type power supply acting as a 
central power distribution hub with computer up-time benifits. Be sure 
to put the tv on one of the filtered jacks not one of the backed up 
jacks. Most UPS's dont like the power spike tv's make when starting.



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