In article ,
Serge Auckland wrote:
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.

Pretty well all domestic Hi-Fi has Class II insulation. So even if metal
cased doesn't need a safety earth. Indicated (in the UK) by only having a
two wire power cable.

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.

While balancing is ideal for the long runs and hostile environment pro
gear oft finds itself in I'm not sure about the validity for domestic use.
Much domestic gear is internally unbalanced so providing a balanced output
might mean adding unnecessary extra electronics.

--
*What was the best thing before sliced bread?

Dave Plowman London SW
To e-mail, change noise into sound.