Buzz/Hum on long audio run - AVS Forum
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post #1 of 8 Old 04-11-2001, 05:13 AM - Thread Starter
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I have run 50 foot lengths of canare low level audio cable from my MC-1 to an upstairs television. I have also run a 50 foot "S" cable. Video seems to be great, and even audio is generally good. However, I have noticed that if the volume is up on the television without sound coming out of the MC-1, I get some buzzing/humming. I have checked the connections, and I have moved the cable around on its route to makke sure it stays away from flourescent lights, etc. as much as possible.

My question is this: Is there any quick fix for something like this, such as some of those add-on rf blockers? Is it more likely that there is a problem with the cables?

Any suggestions would be appreciated!



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post #2 of 8 Old 04-11-2001, 08:35 AM
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Is your line level audio cable running parallel to AC power at any point? This can induce a 60Hz buzz.

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post #3 of 8 Old 04-11-2001, 10:12 AM - Thread Starter
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I can check. I guess the recommended practice is to run the low level lines perpendicular where they have to cross?

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[This message has been edited by BL (edited 04-11-2001).]

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post #4 of 8 Old 04-14-2001, 11:57 AM
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You may want to use a Balanced line transmitter and Receiver from Audio Control. You can also use some Plain Baluns too. This will rid you of the noise.

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post #5 of 8 Old 04-14-2001, 05:12 PM
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You might also want check to see if it is a ground loop problem.

On the Lexicon side of the cable, partially pull out the connectors till the ground of the connectors no longer make contact with the pre-amp's connectors.

If the hum goes away, that's the problem. However, if the hum gets louder, most likely it is picking up the hum somewhere in the run from the Lexicon to the TV. (Likely from the electrical lines)

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post #6 of 8 Old 04-19-2001, 06:53 AM - Thread Starter
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Thanks for the suggestions. I first wanted to eliminate the video hum, and now that I have largely done that, the audio hum sounds a little better. I am going to check it again tonight, and try your suggestions to correct any remaining problems.

Thanks.

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post #7 of 8 Old 04-20-2001, 08:16 AM - Thread Starter
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To give an update, I found out something that came as a surprise to me, namely that eliminating the video hum also eliminated the audio buzz/hum. All I did was use the trick of taking two radio shack 300 ohm converters (used for non-cable ready tv's) and splicing them together. That appears to have eliminated the video hum on the zone 2 television, the audio hum on the zone 2 television, and the video hum it created on the zone one picture.

I will keep my fingers crossed that it will continue to work!

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[This message has been edited by BL (edited 04-20-2001).]

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post #8 of 8 Old 04-20-2001, 05:21 PM
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If there is a shield (drain/bare) wire then tie it to the ground of the source device and float that wire at the destination.

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