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BACK TO REQ 2000 MID-QUARTER ISSUE 1

DEBUZZ & UNHUM TECHNIQUES AT HOME - part 2

INSTALLING INSULATED, ISOLATED GROUND IN YOUR PROJECT STUDIO

BY ROBERT DENNIS

ADMINISTRATOR,   RECORDING INSTITUTE OF DETROIT

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All studios, big or small can have problems with buzzes and hums.  These types of problems can quickly make the product put out by the studio unprofessional or even unusable.

Step 1 of Debuzzing & Unhumming is to establsh a good ground.  A professional studio would call in an electrician to install insolated and isolated ground plugs.  This would assure that the ground pins used in the studio werre at or very close to "0 volts" with no stray hum.

The cost to the professional studioi could be anywhere between $150 and $500 depending on circumstances.  At home you can install an insolated and isolated ground for your project studio that is as good as the electrician's, but for an out-of-pocket cost between $10 and $20.  

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Why You Need A Good Ground

In theory, any of the outlets in a building are supposed to have "0" volts on their ground pins.  NOT SO.  Most outlets have a small voltage (1/2 to 1 volt). This is a high "line level" in audio. the same level as the audio signal you want.  As a project studio grows in capability, this poor ground starts introducing hum into the equipment.

The smaller project studios may not need a better ground now, but could well need one in the future.

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Making A Insulated/Isolated Ground adapter

A piece of equipment can work with a broken ground wire but become an "antenna" for hum & buzz.
A grounding adapter is sold in many hardware stoes for about a dollar.  It is designed to provide a ground to a 2 wire outlet by attaching a grounding pit to the faceplate screw at the outlet  If the unit had instructions, it would say to attach the green wire coming out of the adapter to the faceplate screw on the outlet.  
If We are going to modify this adapter so that the ground wireof the adapter attaches to a long wire that is properly grounded.
The ground wire is long enough to reach the nearest cold-water pipe.  If the wire is less than 25 feet  use a #12 green electrician's wire.   The local builder's supply outlet will sell this by the foot.  If the run is much more than 25 feet you should use a #10 wire.
You splice one end of the wire to the small ground wire of the adapter.  You can twist these wires together and solder + tape them.  You can also simply crimp them.
You will also buy from the builder's supply store a grounding clamp for pipes.  This will be attached to the other end of the wire.
Even if you have a grounded outlet - use the adapter to give you an fully-insulated and isolated ground system

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