ground loops

[Paul Perry]

At 09:37 AM 13/06/98, Gur Milstein  wrote:
>hi DIY.
>what are ground loops,

this is a complex thing, but think this way:

imagine a signal running to an earth.

Now imagine the wire that connects it to earth.

Now instead of assuming that the wire has NO resistance,
realise it has a tiny resistance.

Now imagine that a signal input also shares part of this
earth wire.
Well, if there is a small voltage appearing along the wire
because of the first signal, then it will seem that the 
second signal has this added to it..
and there is trouble.

How to overcome?
1. Use very fat wires.

2. (better)
All earth wires (from Power Supply, from jacks, from subcircuits)
meet at ONE point only. This is called 'star' wiring, because the
earth wires radiate out like rays from a star.

You can also search on "ground loops" FAQ

paul perry melbourne australia