ScotFraser wrote:
Given the elevator noise he mentioned, it sounds like audio is on the same
service as the rest of the building. It won't be cheap but the real fix
should be a separate service with its own isolated ground for audio only.
Scott Fraser

My experience has been slightly different in this regard as I routinely
run sound systems in a venue where the sound power and the feeds for
6 variable frequency drives (Effects winches), and a large air compressor
are all fed from the same distro board. Everything works fine (and it is
quiet). It took a lot of work to get the system to this point, but it was
all local grounding work within the system, we did not need a clean
ground connection (A practice I am dubious about in a TN-C-S (PME)
installation anyway).

The power is *NOISY*, but with decent kit and good wiring practice
this noise stays out of the audio. Would I have liked to have had a
seperate transformer from 11KV? Of course, but even with really nasty
power supplies a quiet setup can be contrived and this is usaually much
cheaper then pulling in a new feed from the transformers.

Regards, Dan.
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