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PostPosted: Fri Sep 05, 2014 12:21 am 
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Location: W 85 14.089 , N 29 41.685
should I run a ground wire to each piece of resilient channel (for safety and RFI)? and If yes how would it be best to connect the ground wire to it?


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PostPosted: Fri Sep 05, 2014 3:18 am 
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Not necessary, except maybe if you have electrical wiring touching or very close to the RC.

- Stuart -

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PostPosted: Fri Sep 05, 2014 5:18 am 
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I I kinda though it wasn't necessary but since i can ground it now easliy would grounding it help against RFI or other induced frequencies / hums into speakers / audio cables kind of like a Faraday Cage?


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PostPosted: Fri Sep 05, 2014 11:15 pm 
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It's not easy to build an RFI shielded room. Notice that portable radios play just fine inside a car.

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PostPosted: Sun Sep 07, 2014 9:07 pm 
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but cars have chassis ground that never sees the earth homes have an earth connection. That is why RF can get into cars easily and not a concrete house with rebar sticking into the ground.


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PostPosted: Sun Sep 07, 2014 10:33 pm 
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In a word - no.

It's a common misunderstanding in all areas of electricity and electronics the Mother Earth acts as a sump or sink for all types of noise and interference currents.

Henry W. Ott has an 850 page book that explains it better.
"Electromagnetic Compatibility Engineering"
http://www.hottconsultants.com/EMCE_boo ... _book.html
http://www.hottconsultants.com/

Jim Brown as about 50 papers that explain it better.
http://www.audiosystemsgroup.com/publish.htm

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PostPosted: Wed Sep 10, 2014 9:42 pm 
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Location: W 85 14.089 , N 29 41.685
On a similar question one of my circuits when I tested it for continuity with my amprob multi-meter beeped as if their were continuity but I did NOT have the hot and neutral twisted together ( How I check for continuity before the power gets connected) Then I finally realized after numerous hours of trying figure where the short was that it only beeped for 5 seconds and figured out after talking to my friend who is the best electrician in the northwest panhandle of florida, it was a phantom 7v caused by some electromagnetic field. My question is will this field potentially cause any problems to my audio signals in a properly grounded isolated ground system especially with the in wall xlr runs 20 ga standard outdoor high quality mic cable?


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PostPosted: Thu Sep 11, 2014 8:23 am 
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The phantom voltage that electricians talk about is a very different thing than a mic pre-amp phantom voltage. What happens is when you have a long wire that's not connected to a circuit and then measure it's AC voltage with a modern DMM meter it will show a voltage. But the minute that you connect that wire to a circuit the phantom voltage disappears. So no, it won't cause any signal problems.

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PostPosted: Thu Sep 11, 2014 10:04 pm 
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but why then is there enough phantom voltage to give continuity for 5 seconds and have none most things read phantom voltage still won't pass a continuity test unless there is continuity


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PostPosted: Sat Sep 13, 2014 3:49 am 
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It's AC noise that the AC meter is reading, it's not stored like a capacitor, it's new noise every power line cycle. Although it can store a DC static charge just like a tiny capacitor.

The DMM meter input impedance is 10 to 100 Meg-ohm or more. So the DMM is drawing about zero current and the long wire is just an antenna. If you just clip a resistor Say 1K or 100K or whatever) across the Red & Black probe leads while you make the measurement the phantom voltage will disappear.

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