Beware old building with additions :P It appears we have power coming
from two power entrances with two different earth grounds to the panels. I
had found two power cords with the ground pin pulled which I replaced...
big ground loop noise. I tried (as read from a number of sources) making
unballanced cables with a small resitor in the ground path but this made
things worse not better. I will be running a power cord from the stage
back to the mixer next. All of our signal in paths are already isolated.
It is only the two monitor mixes to powered monitors that are unballanced
and causing problems. The outputs from the mixer are ballanced, but the
lines to the stage are not... I may make cables to allow me to use two of
the input ballanced lines instead and two more isolation boxes as a longer
term fix. There will be a new stage going in and I have already been
asking that power and grounding be corrected for the whole signal flow.
--
Len Ovens
www.ovenwerks.net