# Audio and video power line interference



## Guest (Jun 6, 2011)

I am not sure where to post this so am doing so in a forum that has a similar thread.

I provide karaoke for parties, with audio and video being provided, using a karaoke player fed into professional audio equipment. Whether or not this happens depends on the particular location's power quality. It only happens once in a while.

At times I get "electrical interference" in the video. It consists of adding random bits of dots and larger bits of color all over the screen, a little at a time. It may be a little bit of it or it may be a lot. In severe cases it will eventually be so numerous as to blot out being able to see the words on the TV screen. I use computer monitors but the problem occurred when previously using regular TVs (RF or video inputs).

I know this is a power line issue as I can unplug from the wall and use UPS battery power and the problem does not occur, until soon after plugging it in again to the wall. I am guessing that it is motor noise from a house appliance (such as a refrigerator) as it comes and goes most of the time (such as when a refrigerator cycles on and off). In other cases it goes away completely as the time gets later, indicating something else that is eventually turned off for the night.

Saturday night I encountered something new, never before in over 11 years of connecting my equipment all over. I had a very loud buzz in the sound. The power line is the problem as when I unplugged from the wall (switching to UPS power only) the buzz completely disappeared. I am guessing it was the pool circulation system but could not verify as the customer would not turn it off for a few seconds to check it. In other situations, shutting off the pool circulation system has corrected the video problem stated above.

I am using a TrippLite Line Conditioner with the UPS plugged into it. Then everything else connected to the UPS outlets. 

Now the question, what can I do to get rid of the power line noise? I have to be able to plug my equipment into (whatever) as I cannot find and isolate the source of the problem in other people's homes and I am only there for a few hours at the most.

If anyone has any ideas how I can eliminate this problem no matter where I am plugged in I would really appreciate it. Thank you.


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## mechman (Feb 8, 2007)

Welcome to HTS. :wave:

Take a look at these threads here and here. :T


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## robbo266317 (Sep 22, 2008)

Welcome abord,

Cheers,
Bill


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