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Author Topic: Distance between electrical and audio cables  (Read 19732 times)

Kevin Graf

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Re: Distance between electrical and audio cables
« Reply #10 on: January 15, 2015, 09:21:30 am »

'jneutron' a huge research laboratory systems engineer (has installed over 150,000 miles of wire & cable) is also a weekend pro audio guy.  He runs AC power and signal cables in the same snake.

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Daniel Levi

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Re: Distance between electrical and audio cables
« Reply #11 on: January 15, 2015, 09:51:37 am »

And, of course, a company such as Sommer Cable that make good quality cables would not make combined audio/power cables (and associated multipin plugs) if they thought it was a problem.
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Steve M Smith

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Re: Distance between electrical and audio cables
« Reply #12 on: January 15, 2015, 03:30:10 pm »

I have power taped to my snake along with ethernet and rf coax.


The only time I have had noise was when I didn't do this.  We had the mixer powered from the same outlet as a follow spot and had some induced noise.  The next day we taped a power cable to our multicore.




Steve.
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Art Welter

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Re: Distance between electrical and audio cables
« Reply #13 on: January 15, 2015, 04:54:39 pm »

Has anyone ever witnessed a noise issue that was fixed by just moving audio cables further away from power cables?
I remember one set of dimmer cables that were so noisy they induced audible hash into loudspeaker cables run next to them- the high frequency noise could be heard with the amplifiers turned off six feet away from the speakers.
Re routed the speaker cables, turned down amp sensitivity, and the noise dropped to a level below ambient crowd noise.
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Scott Holtzman

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Re: Distance between electrical and audio cables
« Reply #14 on: January 15, 2015, 09:21:18 pm »

'jneutron' a huge research laboratory systems engineer (has installed over 150,000 miles of wire & cable) is also a weekend pro audio guy.  He runs AC power and signal cables in the same snake.



There is so much going on in that picture.  The orange extension core is special but that's been covered so many times we will leave it alone.

The contrast is between the carpet covered speakers, the Tektronix storage (I think but not sure) o'scope and the childrens themed wrapping paper ??  Lot going on in that space.

On a constructive note I have never had an issue with parellel power, snake runs now with DMX, AES50, various wired Ethernet etc.  In fact I have been shipping for some sort of lace up harness so I can group it together.  I tried using telco style wax cord (12 cord) with the running stitch and it looks pretty but doesn't stay together after multiple roll ups.  Individual knows would probably do better but I am not that fast anymore so 150' with 300 knows would be a whole day all said and done.
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Scott AKA "Skyking" Holtzman
River Delta Audio is now:

Ghost Audio Visual Solutions, LLC
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www.ghostav.rocks

Mike Sokol

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Re: Distance between electrical and audio cables
« Reply #15 on: January 15, 2015, 09:43:58 pm »

'jneutron' a huge research laboratory systems engineer (has installed over 150,000 miles of wire & cable) is also a weekend pro audio guy.  He runs AC power and signal cables in the same snake.

Back in my early days of doing live sound, and before I understood all this ground loop stuff, I discovered that powering my mixing console from an outlet in the back of the room, and the power amp rack from a stage outlet would sometimes result in a ton of hum. But plugging the console into the same outlet as the power amp rack would always have very low or even zero hum. So I taped a 100-ft extension cord to my mic snake for convenience and never had a problem. I understood that voltages differences between the two grounds were the culprit, and after being shocked a few times from ground-lifted extension cord, I was dedicated to grounding everything.

Nowadays when I need to run copper between two pieces of gear powered by different electrical outlets, I try to incorporate an isolation transformer whenever there's the slightest hint of hum. And don't count on "isolated" or "technical ground" circuits as the ultimate solution. I find that they're sometimes mis-wired and contaminated by electricians who don't understand audio system grounding, and often not worth all the extra expense. 
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Mike Sokol
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Stephen Swaffer

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Re: Distance between electrical and audio cables
« Reply #16 on: January 15, 2015, 10:22:19 pm »


On a constructive note I have never had an issue with parellel power, snake runs now with DMX, AES50, various wired Ethernet etc.  In fact I have been shipping for some sort of lace up harness so I can group it together.  I tried using telco style wax cord (12 cord) with the running stitch and it looks pretty but doesn't stay together after multiple roll ups.  Individual knows would probably do better but I am not that fast anymore so 150' with 300 knows would be a whole day all said and done.

We used to use a nylon fabric sleeve for grouping TIG welding lines (water cooled electrode/return water/gas) came flat-zipper zipped into a tube. These were standard 10' or 12 ' but it seems like I have seen bulk rolls.  Held up well in a weld booth, I would think it would last for sound applications?
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Steve Swaffer

Jonathan Johnson

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Re: Distance between electrical and audio cables
« Reply #17 on: January 16, 2015, 01:51:53 am »

Normal AC service has yet to create any noticable induced noise in our systems.

Unless you are dealing with 115kV transmission lines, in which case you may want to maintain a separation of a hundred feet or more.

(Sorry, I just had to pick an extreme.  ;D )
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Stop confusing the issue with facts and logic!

Nate Armstrong

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Re: Distance between electrical and audio cables
« Reply #18 on: January 16, 2015, 09:03:41 am »

What are your guys thoughts about this device ?
https://www.youtube.com/watch?v=CuvDMjxhE68
if you do not want to watch the video , Here is the an explanation of the video

by  adding large  power rectifier diodes to the ground  it eliminates the 60 hz hum.
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Mike Sokol

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Re: Distance between electrical and audio cables
« Reply #19 on: January 16, 2015, 09:17:41 am »

What are your guys thoughts about this device ?
https://www.youtube.com/watch?v=CuvDMjxhE68
if you do not want to watch the video , Here is the an explanation of the video

by  adding large  power rectifier diodes to the ground  it eliminates the 60 hz hum.

Been there, done that (nearly 40 years ago). Only works for small ground loop voltage differentials (GLVD) up to the forward bias of the P-N junction in the diode. So that's around 0.5 to 0.6 volts for standard Silicon junctions. You can series stack the diodes for a higher GLVD situation, and I used to use really big diodes (40 amp?) for some of my early hum reduction experiments back in the 70's.

I see 1 to 2 volts GLVD all the time, and have personally measured 5 volts GLVD on occasion. My table-top experiments show around 1 amp of current in the shield per volt of Ground Loop Differential, and many types of pro-sumer gear with the pin-1 problem will start ground loop humming at 100 mA of shield current. So even 1/10 volt difference between outlet grounds can make your active floor wedges hum.   
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Mike Sokol
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