isolated ground?/ studio acoustics on the cheap

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c. laszlo koltay
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isolated ground?/ studio acoustics on the cheap

Post by c. laszlo koltay » Wed Dec 14, 2005 4:13 pm

much to my chagrin I recently found out that my whole studio is wired the way standard residential/commercial electric is. the electricians tell me this means each outlet is grounded to the conduit. thankfully none of the conduit touches anything but drywall(no plumbing). I have two separate 150 amp panels, one for the studio, one for my apartment. currently they share the same ground stakes! I have these same electricians coming to separate the ground according to the panels. I asked them what they knew about isolated ground wiring and got the "I think this is over kill." they claim I should be fine after the grounds are separated. the only reason I want to believe them is that I understand that the isolated ground situation requires them to replace all of the outlets which are numerous with new out lets that cost about four dollars a piece. add their labor and this becomes pricey. they also said the plugs I have now can only be wired the way they are with the exception of a floating ground. I will gladly pay for more freedom from the hum in my life I just want make sure I got the right information. I also built a ton of tube traps and panel diffuser/absorbers for beans recently and would be happy to share materials lists and extremely simple instruction with whoever is interested.

thanks,
chris

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Post by stuntbutt » Fri Dec 16, 2005 1:51 am

Well I only know a little about AC wiring so take this with a grain of salt.

I am pretty sure that all grounding electrodes must be tied together on the same service. I am also pretty sure that the term "floating ground" makes no sense.

Circuits with an isolated ground require a fourth wire as a "home run" ground for each outlet. The good news is that you only need an isolated ground on outlets that have audio equipment. Most rigs can run on one or two 20 amp circuits.

I think disconnecting the shield on the input side of all audio devices is more important for eliminating ground loops. [/i]

mpedrummer
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Post by mpedrummer » Fri Dec 16, 2005 6:39 am

stuntbutt wrote:I think disconnecting the shield on the input side of all audio devices is more important for eliminating ground loops. [/i]
Not to be a weenie, but don't do that. Yes, it will prevent hum, but it also is a really big safety hazard.

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Post by stuntbutt » Fri Dec 16, 2005 8:05 am

Safety? I'm suggesting leaving the audio shield disconnected at the input. Did you think I meant the grounding conducter of the AC?

mpedrummer
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Post by mpedrummer » Sun Dec 18, 2005 10:23 am

Yep, my bad. Totally misread your post. Sorry about that.

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Post by lunatic » Wed Jan 04, 2006 9:40 pm

Yes, isolated grounding requires IGR's or Isolated Ground Receptacles (plugs/outles). However, $4 a pop is a great price if they are real IGR's. The cheapest I have seen is at Home Depot for what.. $13 a piece?! I got lucky and got a bunch off a guy on EBay and THOSE were about $3 a piece.

If you have conduit then retrofitting an isolated grounding solution shouldn't be too bad especially if you only isolated the ground for a handful of receptacles. Shop around for the best quote and find an Electrician who has done a studio.

WIth that in mind, you could always have them isolate one or two receptacles and see if it helps.

Is the hum really bad :(

Take care,
Brad

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