[Mr.T]

"Arny Krueger" wrote in message
...
Safety ground is often connected to the chassis of audio gear. Signal
ground
is often connected to the same chassis. Sometimes there is a switch to
make
that connection optional or indirect. IOW, mixing signal ground and power
ground is often unavoidable.

Yep, until recent years when double insulated equipment became common,
nearly all audio gear sold here had the signal grounds and safety ground
both tied to the chassis.

MrT.