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Ground screw on amp chassis? (1 Viewer)

Joined
Dec 11, 2001
Messages
28
Is the ground screw on an amp's chassis for anything other than connecting to a turntable?

I read that you can solve a ground loop problem by connecting

a grounding wire from the amp's ground screw to either the metal box in the electrical outlet or the screw that holds the electrical outlet in the box (top & bottom screws)

Is that true?

Sal
 

brucek

Second Unit
Joined
Dec 29, 1998
Messages
335
Sal,

The ground screw on the amp's chassis is already connected to the items you mention.

In a three prong plug and wall receptacle, the center round conductor is the safety ground. The safety ground is for your protection if a fault inside a piece of your equipment causes the hot 120 volt line to contact the metal case. The safety ground will cause a breaker to trip, otherwise you'd get a shock if you touched the case.

Inside the amp this safety ground is usually connected to an external screw for your convenience.

It can be used as you've said for a turntable or any device you would like to bring to the same ground potential as your amp. Sometimes if you've got equipment plugged into different outlets, there can be a small potential difference between the grounds and this can cause a ground loop hum. Bonding these two grounds with an external wire from this screw can sometimes help, but usually just makes things worse.

brucek
 

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