Help: Velodyne VDR12 LFE input shocked me and is humming - AVS Forum
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post #1 of 6 Old 02-06-2011, 02:09 PM - Thread Starter
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Hey guys, I've been doing research on Ground Loops as my new Velodyne VDR12 definitely has a humming noise (and gets louder as I increase the crossover). While that is the one concern the other concern is the current it's pushing through the wire.

W/o connecting the LFE input to anything, if I touch the end of the RCA wire, there's definitely a current flowing from the sub through the wire. Is this normal?

I did some reading on directional sub wires, etc. to get rid of the ground loop humming, but I'm still concerned that live current is flowing through that wire.

Farhan
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post #2 of 6 Old 02-06-2011, 06:21 PM
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Sounds like a floating ground, meaning the ground is not grounded. Does the sub have the third plug going into the AC outlet in the wall? If so, does it also have the third plug where the AC cord plugs into the sub? If there is a ground plug all the way to the sub, you need to check your outlet. Your ground may have come loose. The best way to do this is to get an outlet tester. Small device that plugs into an outlet, and has three lights on it that tells you if the outlet is wired correctly.

If there is no ground going into the sub, then the sub derives its ground from the RCA wire which is grounded through the reciever (hopefully)

it is best not to plug or unplug an input to a sub with the power on. Leads to nice loud pops which could cause damage.
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post #3 of 6 Old 02-06-2011, 06:32 PM
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post #4 of 6 Old 02-07-2011, 04:21 AM
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post #5 of 6 Old 02-13-2011, 09:23 AM - Thread Starter
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Thanks for your help guys. As it turns out, I did have my sub powered off, but the current was still flowing through. Odd.

So I purchased a few things, hopefully one will solve the problem.
* Ground loop isolater from Monoprice (suggested above)
* longer higher quality sub cable (right now I have shorter cables that are extended)
* RCA splitter, to try the L/R inputs instead of LFE

I'll report back once MP ships all my stuff. Thanks again, looking forward to less hum and less shock

Farhan
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post #6 of 6 Old 02-21-2011, 11:29 AM - Thread Starter
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Alright the humming has been greatly reduced. It's mostly due to a higher-quality cable w/o extensions.

I'm still miffed that there is current flowing through the wire (even when the power is off) so I'm thinking I need to duct-tape or heat-shrink both the Sub side and amp side as just touching the connector causes current to go through your hand
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