On 7/6/2012 2:42 PM, Jerry Kaidor wrote:
> It reminds me of the importance of ground loops.
> Ground loops and me - we have a history.
There is no such thing as a "ground loop" -- it is a totally false
concept. The actual cause of the hum/buzz problems we blame on these
imaginary "ground loops" are LEAKAGE CURRENT from the AC power system,
the IR drop in the green wires puts that voltage between the chassis,
and is added to the signal when unbalanced interfaces are used.
The leakage currents are the result of capacitive coupling between the
phase (hot) power conductor and the chassis, which, by law, must be
connected to the green wire, and from there to the breaker panel. There
are excellent reasons for that connection, all related to safety.
The simple solution is to first get all power for interconnected
equipment from outlets that share the same green wire or from outlets
whose green wires are bonded together; and second, to bond from chassis
to chassis of interconnected equipment with short fat copper.
73, Jim K9YC
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