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Author Topic: Long XLR run alongside 120v AC in conduit  (Read 3062 times)

Ehrack

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Long XLR run alongside 120v AC in conduit
« on: January 13, 2015, 06:57:47 pm »

Hi there,

I need to run about 200 feet of XLR cable that will be carrying a signal from a mixer to some powered speakers, and the wire all needs to be in conduit. Would it be ok to also run the power for the speakers through the same conduit? I am using 1/2 inch steel conduit.

Thanks for the help!
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Jim Williams

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Re: Long XLR run alongside 120v AC in conduit
« Reply #1 on: January 14, 2015, 10:40:36 am »

You will get capacitive crosstalk doing that. Leakage might be at around -30~40 db or so. Never run speaker level cables parallel to low level line or mic lines.
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Fletcher

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Re: Long XLR run alongside 120v AC in conduit
« Reply #2 on: January 20, 2015, 02:44:19 am »

I'm guessing you're talking about 120vac for powered monitors running next to +4 balanced lines to feed those monitors?  200 ft. is a bit long for that kind of run... you could quite possibly get some 120Hz [and 60, and 180, and 240Hz] hum induced in the audio lines.

Conduit is cheap enough... have the electrician run power to an outlet located near the monitors and keep the AC away from your audio lines if you have the option.

If you're talking about running the output of an amplifier [speaker level lines] -- then locate the amplifiers MUCH closer to the speakers and run +4 audio to the amps.  I've always found that the shortest run from amplifier to speakers is best.

I hope this is of some assistance.

Peace
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CN Fletcher

mwagener wrote on Sat, 11 September 2004 14:33
We are selling emotions, there are no emotions in a grid


"Recording engineers are an arrogant bunch
If you've spent most of your life with a few thousand dollars worth of musicians in the studio, making a decision every second and a half... and you and  they are going to have to live with it for the rest of your lives, you'll get pretty arrogant too.  It takes a certain amount of balls to do that... something around three"
Malcolm Chisholm

endarn

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Re: Long XLR run alongside 120v AC in conduit
« Reply #3 on: January 23, 2015, 12:07:20 am »

I had read was very impressed.

Diminished Triad

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Re: Long XLR run alongside 120v AC in conduit
« Reply #4 on: March 19, 2015, 07:44:37 am »

A year ago a very experienced sound engineer here quickly diagnosed the various hums i had on stage and those above were right at the top. Today, I don't run power and speaker cable lines anywhere together, and I also don't "curl" up lines of any type but instead leave them laying out in neat lines as opposed to "coiled" up.  Has really made a difference.

Mike
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Fletcher

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Re: Long XLR run alongside 120v AC in conduit
« Reply #5 on: March 19, 2015, 09:22:26 am »

Good thought... "inductive loops" can indeed be an unnecessary pain in the arse.  All "alternating current" events will create a field around the source wire which is why you need to be careful about where you lay your audio lines in relationship to your "power" lines.

In the best of worlds you can entirely avoid running the two parallel to each other... an intersection at 90˚ is best [lowest point of potential "field effect" transmission].

Peace
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CN Fletcher

mwagener wrote on Sat, 11 September 2004 14:33
We are selling emotions, there are no emotions in a grid


"Recording engineers are an arrogant bunch
If you've spent most of your life with a few thousand dollars worth of musicians in the studio, making a decision every second and a half... and you and  they are going to have to live with it for the rest of your lives, you'll get pretty arrogant too.  It takes a certain amount of balls to do that... something around three"
Malcolm Chisholm

steve p

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Re: Long XLR run alongside 120v AC in conduit
« Reply #6 on: April 09, 2015, 03:00:22 am »

Yea, keep them in separate PVC runs.  If the audio wires need to cross the AC wires somewhere keep it like this... +  like others said Not Parallel.

:)
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Steve Perkins


Creation Recording Studios

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