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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Mike Sokol on April 20, 2015, 01:51:43 PM

Title: Isolated Grounding
Post by: Mike Sokol on April 20, 2015, 01:51:43 PM
Here's a pretty good discussion in EC&M about why a totally separate grounding system for sensitive electronics is not acceptable. Seems to apply to our own power distro situations such as recording studios and live stages. There's also a pretty good discussion on keeping extraneous noise out of the grounding system in the comments section. You'll probably need to create and use an EC&M logon name if you want to put in your own 2 cents (or is that 2 pence?). But it appears that you'll be able to read the article without having to use an EC&M login. However, let me know if you have trouble reading the article and I'll re-paste the entire thing here. (

Title: Re: Isolated Grounding
Post by: Kevin Graf on April 21, 2015, 09:57:14 AM
An EE's blog:

"Discussion on RS232 Ground Noise, Grounding, and Isolation"
by Gordon A. Roberts

and some interesting power tid-bits:
Title: Re: Isolated Grounding
Post by: John Roberts {JR} on April 21, 2015, 11:18:23 AM
Agreed... EGC paths should never be common to or carry sensitive signal currents. (Audio grounds can connect to safety grounds but not share common paths where signal and noise currents could mix together.)

Some of this distress may be related to legacy (old) design where active components (like tubes) were very expensive (and not very low noise). The duplication of active devices to balance differential signal handling interfaces was a premium few could afford, and any active component noise floor increase was undesirable.

Modern electronics are relatively cheap and low noise. For most applications modest noise voltages from currents flowing in EGC can be held common mode and do not have to contaminate sensitive signals.

Title: Re: Isolated Grounding
Post by: Jerome Malsack on April 22, 2015, 11:40:14 AM
Looking at this  Leaves me wonder on the use of computers to monitor the amplifiers, 

but mostly wireless mics monitor and noise levels with the computer tie.  USB or RS 232 

Believe that this will be based on the computer and its build.  Computers are not keeping up with the grounding and configurations that the audio world was seeing.