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 Ground Loop

Q. I noticed a weird digital noise, hum or buzz coming through my speakers when music is not playing


In most cases, this is caused by a ground loop or earthing problem. It can also come from the laptop's power supply.

You will need to purchase and use a ground loop isolator on each of your audio connections from you computer to eliminate this problem.

If you are using master+headphones sound setup, you will only need one ground loop isolator. If you are using an external mixer setup, then you will need a ground loop isolator for each audio connection (Typically 2 or 4.)

If the noise is a high-pitched 'mosquito' type noise rather than low-pitched hum/buzz, then it may be caused by the laptop's power supply. Typically power supplies with a ground connection (Clover-leaf rather than figure-of-eight connector from mains into the power supply 'brick') cause this problem.

A ground loop isolator will eliminate this problem in most cases, or you may be able to replace the power supply with a suitable rated and manufacturer approved alternative that is double-insulated (Figure-of-eight connector.) Please contact the manufacturer to check whether a suitable alternative power supply is available.

You can easily and safely check whether your laptop power supply is causing the problem. Simply disconnect it from the mains and run your laptop from battery. If the noise stops, then the laptop power supply is causing the problem.

Here are a video explaning about the common ground loop problems:
https://www.youtube.com/watch?v=4YM1iwC6vhg

And here a sample of a ground loop isolator: http://www.radioshack.com/ground-loop-isolator/2700054.html#.VTEMbpM6blZ

WARNING: NEVER remove or isolate the ground pin of the mains cable. It is there for a very important reason and in the event of a fault may save your life. If you remove the ground connection, then you could be seriously injured or even killed in the event of a fault.




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