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Author Topic: Test for damaged mic cable?  (Read 2602 times)

Mark Lemaire

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Test for damaged mic cable?
« on: November 21, 2011, 01:25:34 pm »

There have been many discussions here about long mic cables picking up RF, etc. I do most of my recording  as an "on location" in classical engineer. MIC cables are 100-130 foot lengths on reels and are run from the stage to my CR. I've had no problems with RF.

The other night a thing that I have tried to avoid at all costs finally occurred- and the overzealous stage crew rolled a loaded dolly (with hard 4" wheels) across my cables- twice! I am not sure if they damaged the cables, or if they are OK. Obviously I can check for continuity and the signal passing thru, but I am more concerned about possible damage to the shielding.

Is there at test that I can try at home? I don't want to find out at my next orchestral gig that the cables are now picking up extra hiss or radio.
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klaus

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Re: Test for damaged mic cable?
« Reply #1 on: November 21, 2011, 01:35:48 pm »

You can move a strong AC or magnetic field all across the stretched-out cable, as you monitor for noise.

If the shield was damaged (not SEVERED-you can test THAT possibility easily with a continuity test- from connector end to connector end, after removing the shield terminations from the ground), you would pick up more RF and other noise at the cable section under suspicion.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

Mark Lemaire

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Re: Test for damaged mic cable?
« Reply #2 on: November 21, 2011, 04:59:23 pm »

Good idea! Suggestion of a household item that might have a strong magnetic field? I have a Han-d-mag sitting around here - wave it over the suspected area?
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klaus

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Re: Test for damaged mic cable?
« Reply #3 on: November 21, 2011, 05:39:34 pm »

A HandiMag is a good start.

You can also move the cable over one of those 120-12V converter boxes commonly used with halogen 12V lighting. The converter usually comes as a wall wart:  2 prongs for 120V AC and a small wire or female plug on the other side, for the 12V Halogen fixture.
That is what I usually use when I suspect a bad shield.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com
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