| Grounding, dirty power or whatever it is... [message #316820] |
Tue, 19 February 2008 04:38  |
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 judah
Messages: 274
Registered: April 2004
Location: Italy |
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Hi all,
I've been rebuilding my studio in the past few months and there's a problem that's driving me crazy. The studio is in a industrial lot with lots of factories goin' during the day. I have a quite simple setup: a mixer, a computer, a rack with some stuff and that is it. Well, during the day I have a huge amount of noise coming off monitors and guitar/bass amps as well. Just around 6/6.30PM, when all the factories shut down, the noise disappear and the studio is quite as death. No hum, no hiss, no buzzes, no cracks, nothing.
Where should I start troubleshooting?
THX.
R-
Ronnie Amighetti
DIESEL
Laboratorio di registrazione sonora
"I'm fucking busy and vice versa."
Dolly Parton
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| Re: Grounding, dirty power or whatever it is... [message #316834 is a reply to message #316820 ] |
Tue, 19 February 2008 06:58  |
sodderboy
Messages: 152
Registered: June 2006
Location: Huntington NY |
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The motors, solenoids, etc. in the factories present reactive rather than resistive loads to the AC supplied to the industrial estate. The machines throw spikes and all sorts of 60HZ harmonics back into the system.
There are some deeper descriptions of what is happening here at, gulp, here we go, um, Equitech- there I said it!
http://www.equitech.com/articles/articles.html
Remember though that all of the "solution" content is sales copy!
The easiest thing to do about the noise is of course to change business hours. Next is to get a simple "isolation transformer" and a separate surge suppressor from a company like Square D. One better is to get a constant voltage transformer from Sola. That is a solution that will heal all problems. Both of these products are available in sizes from small to large on ebay.
In an industrial estate, I would go directly to the SOLA. All sizes and phase configurations are available on ebay or salvage companies- you might even have one in the estate.
http://www.solaheviduty.com/products/powerconditioning/Index .htm
How much juice is your panel? To condition only the studio equipment, you can make a sub-panel post lighting and HVAC and use a smaller transformer.
Mike
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| Re: Grounding, dirty power or whatever it is... [message #316862 is a reply to message #316837 ] |
Tue, 19 February 2008 09:05 |
drknob
Messages: 41
Registered: February 2005
Location: Montreal, QC |
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You could also get yourself an MGE Pulsar EXRT 2200 ups. It is a true online ups, regenerating perfect sinusoidal 120V 60Hz power with, I believe, power factor correction. It will make power line disturbances irrelevant and protect you from outages as well. At 2200 watts, it can run a lot of stuff. You wont get that with (shudder) Equitech.
Oops....they have 220V products too.
BTW, be careful - not all ups units are on line. Some just switch between mains power and battery backup when needed. An on line ups constantly regenerates power, with the added benefit that there is no switching transient when moving to battery mode.
Harold Kilianski
CIRMMT, McGill University
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| Re: Grounding, dirty power or whatever it is... [message #317109 is a reply to message #316820 ] |
Tue, 19 February 2008 23:31 |
John Monforte
Messages: 172
Registered: January 2005
Location: Miami FL USA |
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I wouldn't run out to buy power line filters before determining if the noise is in fact coming from there. More commonly, this junk is radiating in the air and gets into the audio inputs through inductive or electromagnetic coupling.
Try a shorting plug into the inputs of your guitar amps and see if that changes things. Try lifting ground. Is it worse with dynamic mics compared to transformerless condensers? This is worth some experimentation.
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| Re: Grounding, dirty power or whatever it is... [message #317501 is a reply to message #316820 ] |
Thu, 21 February 2008 08:31 |
drknob
Messages: 41
Registered: February 2005
Location: Montreal, QC |
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A true online ups also acts as an isolation transformer. It's more expensive (and heavier) because it has two transformers - an input and an output which are always in circuit. Cheaper 'switching' upses share one transformer which switches between input (charge mode) and output (generate mode). In pass through mode, they just connect directly to the power line with some filtering - no isolation.
BTW, cleaning up your electrical distribution system is the most important place to start. Don't put too much faith in separate technical ground. It's a false assumption that all the bad stuff will simply disappear down the magical ground drain. You need to take care of the other stuff first.
Harold Kilianski
CIRMMT, McGill University
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| Re: Grounding, dirty power or whatever it is... [message #318182 is a reply to message #316820 ] |
Fri, 22 February 2008 22:10 |
John Monforte
Messages: 172
Registered: January 2005
Location: Miami FL USA |
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Sorry to hear about the expense and trouble you are having. New ground rods only fix problems that come from bad ground rods. It appears you did not have a ground rod problem.
Perhaps you missed my earlier post.
The best way to arrive at the correct answer is to first understand the problem. Noise is not the problem it is the symptom. Simply trying solutions can be expensive and frustrating.
Your original post did in fact ask about troubleshooting, but most of the later discussion has been about solutions, not troubleshooting. I am confident that if you approach the problem in a way that is systematic and repeatable, you will find where the noise is coming from. Then the answer will be evident - and probably not expensive.
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