"Jim Lesurf" wrote in message
...
In article , Bob Latham
wrote:
In article , Rob
wrote:

I can't explain I'm afraid - but a NAD tec advised retain the ground
at the source, and open at the other end.

Hmmm. I've learnt from reading forums like this, that this is the
considered the way to do it ie. connect screen at source and disconnect
at destination.

I think Jim once tried to convince me there was a good reason for that

Afraid I can't recall what I may have said. However...

It can make sense *if* you have a loop which is causing hum. *However* it
would be preferrable if that could be fixed in some other way. The
difficulty is that hum generation can me more complex than the simple
descriptions, and sometimes some actions are impractical, so you end up
with a less-than-ideal solution.

A better way - if possible - is to lift the grounds from the mains
connections of all units *except one*. And then make sure all screens are
connected at both ends and used for ground path return.

A practice I find dangerous, in that if the audio connections are removed,
then a piece of equipment can be left powered-up but ungrounded, with
obvious danger in case of an electrical fault. I much prefer the practice of
having seperate audio and safety grounds, grounding every safety ground and
joining the audio ground to safety ground at one point only in an
installation. This is pretty much standard practice for Broadcast equipment,
sadly not yet for consumer stuff. With increasing numbers of "high-end"
equipments offering balanced connections, it would be fairly easy to offer
seperate audio and safety grounds.

rest snipped

S.

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