View Single Post
  #3   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Polarity/Ground Questions

Gary Vee wrote:
I live in an older home with non-grounded electrical on the 2nd floor. The =
house had been remodeled and they installed GFI receptacles throughout. I w=
ould expect these to provide the necessary protection if needed.


This is legal and meets code. The GFI provides all needed safety and
obviates the need for a "PE" safety ground.

The GFI does not provide a common ground for RF protection, however, and that
is sometimes an issue for audio applications.

Devices that use shunt capacitors to ground for filtering (like guitar amps
and some computers) will not filter noise effectively and may pop the GFI.
If this is a problem, pull a cable and install an isolated ground outlet for
these things.

My questio=
n is related to audio equipment with grounded AC connections. Does a free-f=
loating ground effect the proper operation of interconnects between balance=
d equipment?


Not really. If anything, it's an advantage because it allows you to break
ground loops more easily.

As mentioned above, it does not keep all of your shields at the same potential
as the physical earth, and that can make low frequency noise problems worse
at times. That's a small issue in most cases.

Also all the outlets are connected to one phase. I read some years ago that=
it's recommended to divide up power usage between the line phases.


It is, but other outlets elsewhere in the house are on the other leg, so
on the whole they should balance out.

It would really be difficult to install new wiring so I'm wondering if it w=
ould be worth the trouble to upgrade the wiring.


I wouldn't upgrade it, but if you have noise problems or you are determined
to use an amp that pops the GFI, I'd pull a single cable and add another
circuit up there, with additional receptacles. I wouldn't remove the existing
ones because you can never have too many.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."