Ground loops, balanced vs unbalanced and ETC


#1

Hi there,

I have used my ETC live a few times but will be behind the mixing desk with the sound guy this time instead of on stage. I got this email from the venue and wondering if anyone can tell me if I am ok to go ahead or not?

“Hi
Shouldn’t be too hard to get a feed - even a configurable one off the desk
What’s the input to the vj setup? Something balanced would be ideal as I suspect the projector is on a different circuit so has the potential to create ground loops when connected to the desk
w”

I know groung loops can damage gear as well as just cause unwanted noise! Can anyone help me figure out if I am in danger of frying any of my gear? Apologies if I am missing anything really obvious! I use an HDMI to VGA converter and a synthstrom deluge to automate the CC messages on the ETC.

Thanks in advance!


#2

I was talking to a friend who thought it would be ok if “…the hdmi output (which is the one that would be possibly grounded to the projector) is not directly electrically connected to the audio input ground on the ETC”.

I’m not sure about the wiring of the ETC…


#3

on the ETC both HDMI port and audio input are tied to the same ground. if you are worried about ground loops you could check out an isolation box like this:

https://www.bhphotovideo.com/c/product/535379-REG/Ebtech_HE_2XLR_HE_2_XLR_Dual_Channel.html?ap=y&gclid=EAIaIQobChMIucHIuOb73AIViQOGCh0boQq6EAQYAiABEgKcpvD_BwE&smp=y


#4

That should sort it and I have something very similar to that isolation box I can use. Very helpful, much appreciated!