[LAU] ground loop hell

[Jan Depner]

On Sun, 2015-02-08 at 09:06 -0800, Len Ovens wrote:
> 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. 


I've been doing that for the last 5 or 6 years as well.  It also keeps
you from getting the crap shocked out of you when you're playing guitar
and singing ;-)


> 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
> 
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