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Electrical Buzz Help!!
Old 17th September 2012
  #1
Here for the gear
 
🎧 10 years
Electrical Buzz Help!!

Hello all,

Not sure if this is the correct place to post this - but I am desperately trying to eliminate some electrical buzz in my studio. I have a room in a basement of a building and from between 9am to 6pm I have a strong hum coming through my speakers - and all transformers in the studio have the same kind of buzz coming out of them. I have not been able to establish what is causing the buzz, and I have very little control of what else is going on in the building.

To that end I have tried the following to eliminate the problem:

1) Unplugging everything and plugging them in one by one - nothing helped
2) Having all equipment tested for faults - no problems
3) I bought an Airlink balanced transformer 2000VA 230v to 230v CTE Three UK sockets (link here - CBS2000). Absolutely no change.
4) Given number 2 and the fact that 3 didn't work, I tried removing the earth from the power source (I know this is very dangerous, but I was desperate to see if this would help) - no change.

Does anyone have any suggestions as what might be the problem, or indeed a suggested solution.

Any help would be amazing,

Thanks guys,

Paul.
Old 17th September 2012
  #2
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Richard Crowley's Avatar
 
🎧 10 years
Are we to presume that none of these pieces of equipment exhibit this symptom when plugged in somewhere else (at home, for example)? And that none of these pieces of equipment exhibit this symptom in your studio outside the hours between 9am and 6pm? And that it is not practical to move your studio elsewhere?

The usual "trouble-shooting" (AmEnglish) "fault-finding" (BrEnglish) techniques apply.

What kind of building is this? Offices, apartments/flats? What is going on in the other parts of the building from 9am to 6pm? If the interference is that regular, presumably it correlates with some other tennant's activities during business hours. Is it practical to go around to all the others and make a quick survey of how they use electricity to see if you can discover the source of interference?

Have you considered contacting your electric utility provider? Or an electrician who could deploy a line monitoring device to log the interference?

Are you saying that the mains hum/buzz is only audible in the monitor speakers? Or do you mean that it is getting in elsewhere (through the mic inputs, for example) and you are only noticing it in the monitor speakers?

While everything is plugged in and turned on. What happens if you disconnect the mains power from the monitor speakers (or amplifier)? Does the hum go away instantly, or does it fade away as the amplifier dies? i.e. are the monitors themselves collecting the interference, or is it something upstream (like the mixer).

That CBS2000 product doesn't really make any claims about filtering noise from the power mains. Certainly there are products that are DESIGNED specifically for power mains noise filtering.

See also this epic discussion of a similar interference problem from neighbors (work-in-process)...
https://gearspace.com/board/geekslut...io-system.html
Old 17th September 2012
  #3
Gear Guru
 
tINY's Avatar
 
1 Review written
🎧 15 years


Did you home-run your transformer all the way back to the breaker panel?

Have you looked at the ground rod that the breaker pannel is tied to?

Do you have any gear with batteries that can operate when not connected to the mains?

What is the spectral content of the buzz?



-tINY

Old 17th September 2012
  #4
Here for the gear
 
🎧 10 years
Thanks for the quick replies guys. I'll try and answer both your questions as best I can:

1) Correct - none of these pieces of equipment exhibit this symptom in other locations
2) It is not really practical to move the studio
3) The building is a church, that I use the basement of - it is an old building that has been completely modernised inside, including all electrical systems. Apart from my studio in the basement, there are two shops that share the building as well as the church itself. As I understand it, the shops are on a different phase of electricity from my studio and that of the church (to be clear - the church and I share the same electrical mains).
4) I have not considered contacting an electrician about a line monitoring device, as I was not aware of this as a possibility - does this just tell you that you have a problem, or does it go some way to resolving the issue?
5) The mains buzz is not only audible over the monitors, but also manifests itself in making my normally quiet transformers buzzy. In addition I get interference in my wave forms when recording which can be resolved by filtering from 60hz down. The mikes I tend to use have mains transformers on them, so this could be how it's leaking into the system when recording.
6) From memory I believe the buzz it fades with the power amp in the monitor, but as I'm not there right now, I would need check. What I do know, is that with nothing else plugged in - either audio leads or electricity, both powered monitors will buzz.
7) No I have not tried running my transformer all the way back to the breaker panel, and am not sure I can do this, as - as mentioned earlier - I share my mains with the church upstairs.
8) No not looked at the ground rod that the breaker panel is tied to, but given that I tried lifting the ground all together, and this made not difference whatsoever, I don't think this is the issue - that said I can do this when I go in tomorrow - what would I be looking for?
9) Yes I have an old Boss drum machine from the 80's that works off of batteries - what's your suggestion?

Thanks again for your responses!

Cheers,

Paul.
Old 17th September 2012
  #5
Here for the gear
 
🎧 10 years
Hey rcrowley,

Aso just to clarify, my thinking with the CBS2000, was that as it is effectively a transformer, it would clean any electrical noise - this is probably an assumption based on my lack of knowledge!

I will have a look at that other thread you mentioned as well.

Cheers,

Paul.
Old 17th September 2012
  #6
Gear Guru
 
tINY's Avatar
 
1 Review written
🎧 15 years


If the buzz is only the fundamental (60Hz and lower), then it's not likely conducted noise from machinery. If it's a pure 60Hz, then I'd suspect neutral/ground issue.

To check for radiated hum issues, use the battery operated device to see if it's picking up the hum.




-tINY

Old 17th September 2012
  #7
Here for the gear
 
🎧 10 years
Hey tINY,

To clarify (and sorry I forgot to mention in the last post), I get 60hz and lower interference coming through on actual recordings (this may or may not be part of the same problem), however the buzz coming through the monitors is across a range of frequencies, though most prominent in the mid frequency range - I reckon around 2khz, but Ill check this as well when I go in tomorrow. All my wall warts are buzzing at around the same freq as well, and indeed the CBS2000 itself. As mentioned before, I have tried removing all of these things out of the chain, but to no avail.

Will check your radiated hum idea tomorrow, I will also try a dynamic mic, to see if the rumble problems in my recordings are being caused via the mic's transformer being give dirty mains...

Cheers,

Paul.
Old 18th September 2012
  #8
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Richard Crowley's Avatar
 
🎧 10 years
Is this ACOUSTICAL buzz from the devices themselves?, or is this SIGNAL hum, noise coming along with the audio signals? If wall warts are buzzing (presumably acoustically?) you may have a serious problem that is putting your equipment at risk. I wouldn't waste much more time before calling out reinforcements. This could be a symptom of a serious electrical hazard that the power utility needs to know about.

"across a range of frequencies" does not sound like power mains "buzz". Depending on where you are, (please complete your user profile at least to reveal what country you are in) the power mains is 50Hz or 60Hz, and power line garbage tends to be harmonics of the fundamental power frequency. Broadband noise is a very different kind of problem.

Just because the shops are on different phases doesn't preclude them from being the source of the noise. If you are really serious about fixing this problem, sooner or later you MUST go around and visit all the power users in the building. Even if you have to dedicate 9am and 6pm for several days going around and spying on what turns on or off at those times. You have an enormous clue in those start and stop times. Don't squander it.

You can rent (or have an electrician rent) power line monitors which monitor and log conditions on the circuits. There are commercial electricians who specialize in tracking down power problems, maybe even the local utility.

Can we assume that you have already checked all the usual things, voltages, neutral and ground integrity, etc. etc.
Old 18th September 2012
  #9
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Ike Zimbel's Avatar
 
🎧 10 years
Hi Paul,
Just to clarify, you are saying that all of your mains transformers, wall warts etc are PHYSICALLY humming, yes? To me that speaks to either the voltage going way down (or maybe way up) while the church is open for business, or else something they are using, like possibly their lighting fixtures, is putting a load of trash on the line.
To start, I would get a good DMM and take some voltage measurements during the day when you have the noise, and evenings when you don't.
The usual measurements between ground and neutral would be helpful, as would letting us know your location.
Best,
Ike
Old 18th September 2012
  #10
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Ike Zimbel's Avatar
 
🎧 10 years
Ha! As I was typing the above and got to the part about your location, I almost put "before rcrowley asks you..." but thought better of it. Rcrowley, I share your frustration with trying to dispense free advice to folks who could be halfway around the world, or next door, but can't be bothered saying.
Cheers,
Ike
Old 18th September 2012
  #11
Lives for gear
 
🎧 5 years
We should remind everyone that the power system in Great Britain is very different from the US & Canada system. Once past the wall receptacle, typical US problems and solutions don't apply.

Oh it's 50Hz not 60.
Old 18th September 2012
  #12
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JohnRoberts's Avatar
 
🎧 10 years
Measure the mains voltage...

JR
Old 18th September 2012 | Show parent
  #13
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Richard Crowley's Avatar
 
🎧 10 years
Quote:
Originally Posted by Speedskater ➑️
We should remind everyone that the power system in Great Britain is very different from the US & Canada system. Once past the wall receptacle, typical US problems and solutions don't apply.

Oh it's 50Hz not 60.
Skincod has updated his profile to reveal that he is in London.
He did not report that he had actually measured the mains voltage under the two conditions (during the interference and without it).
I fear that such an unusual display of symptoms may indicate a serious problem that is dangerous for an amateur to attempt to deal with.
Dangers to both life and property.
Old 18th September 2012
  #14
Here for the gear
 
🎧 10 years
Hi All,

Yes - there is acoustical buzz from the wall warts (more than is normal, and it sounds suspiciously similar to that coming from my powered monitors).

From what you all seem to be saying, this may suggest I have a fairly serious problem. To that end I'm going to try and get someone down to measure everything properly, as I have no desire to electrocute myself!

Will let you know what there is to report back as soon as I have data.

Thanks all again for your replies - please let me know if there is other information that would be useful in determining these problems - it's not that I can't be bothered to let you know the info, it's that I don't know what info is relevant - I will always give as full a picture as I can.

Thanks again,

Paul.
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