Login / Register
 
Chasing Hum...
New Reply
Subscribe
TC5
Thread Starter
#1
27th April 2010
Old 27th April 2010
  #1
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Chasing Hum...

Oh the joy. I'm having a problem with humming and buzzing noise. So much so that even my humbucker guitars are humming almost as much as single coils. I guess the main thing to look for is ground loops and such?

I already tested the main outlet and the ground seems fine. Everything is plugged into the same power conditioner (via a power strip). I don't know how a ground loop can happen in this case.

There IS a radio station not too far so I'm also getting radio interferences... So what are my option besides turning the room into a faraday cage?
__________________
Downtempo, Chillout, Lounge on Soundcloud
https://soundcloud.com/tc5-1/time-in-between
We have reached the limit of what anal probing can teach us.
#2
27th April 2010
Old 27th April 2010
  #2
Lives for gear
 
brianroth's Avatar
 
Joined: May 2005
Location: Salina, Kansas
Posts: 2,180

brianroth is offline
Your guitars are picking up the racket, without any "DI splits", etc?

If so, then the problem is in the immediate environment. Common sources are fluorescent lights, electronic light dimmers, and even mundane stuff like aquarium heaters.

As for the RF problem, that is a whole other story.....

Best,

Bri
__________________
Brian Roth Technical Services
Salina, Kansas...home of the BEST vinyl on the planet and excellent suppliers of Pro Audio and High End Hi-Fi Gear

www.BrianRoth.com
http://recordingservicesandsupply.com/
http://store.acousticsounds.com/
http://www.qualityrecordpressings.com/
#3
27th April 2010
Old 27th April 2010
  #3
Lives for gear
 
Joined: Sep 2004
Location: UK
Posts: 6,768

Matt Syson is online now
Hi
Sounds like the classic 'mains loop' problem which is NOT a ground loop but a situation where the current going to an appliance, light or whatever is not returning by the EXACT physical route that the 'go' current is taking. This is easy to get wrong when wiring '2 way switches' for lights and ideally the 'go' current conductor is twisted with the 'return' current conductor all the way from the fuse distribution box to every one of your lamps or whichever.
Having the go and return currents as a 'twisted pair' will not produce any significant radiated hum, it is just a bit tricky to do physically.
As Brian said, RF pickup is another can of worms although COULD be related if your installation wiring is poorly laid out.
Matt S
__________________
Matt S
www.mseaudio.co.uk
TC5
Thread Starter
#4
27th April 2010
Old 27th April 2010
  #4
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Thanks both for the input.

One thing that was done years ago was that the power outlets which were originally not grounded (old house) where grounded by connecting the ground to a water pipe. This was done only in this room. Could that have the potential to cause problems?

Matt it sounds like you may be on to something. How would I go about verifying / diagnosing this possible mains loop?
#5
27th April 2010
Old 27th April 2010
  #5
Lives for gear
 
Joined: Sep 2004
Location: UK
Posts: 6,768

Matt Syson is online now
Hi
Take a THICK ground wire from your mains distribution board which hopefully has the grounds from all the sockets in your house 'spurring' from it. The other end of this thick ground wire goes to water pipes and possibly an earth spike if you want. This would require a second piece of the thick wire and the 2 of them join at the distribution board.
You should not be having any 'odd' grounds formed by taking socket ground wires to bits of pipe.
Do some reading about wiring regulations and when you are starting to understand them get an electrician in to sort it out properly as 'ad hoc' grounding should be illegal.
Overall it MUST be SAFE otherwise the relatives of former friends that get electrocuted will sue you!
Also read up the many threads on earthing but the decider HAS to be your local electrical regulations.
To sort out the possible loop you must open up and identify ALL wiring which I again suggest you get a GOOD electrician to do. It may cost, getting some new wiring pulled in but you will go around in circles if it is not done properly.
Matt S
TC5
Thread Starter
#6
27th April 2010
Old 27th April 2010
  #6
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Quote:
Originally Posted by Matt Syson View Post
You should not be having any 'odd' grounds formed by taking socket ground wires to bits of pipe.

'ad hoc' grounding should be illegal.
Matt S
Thanks. So are you saying that the ground that was made with a wire to a pipe in a single room is an odd, ad hoc grounding, and therefore should be removed and ground sorted out at the source?
#7
28th April 2010
Old 28th April 2010
  #7
Lives for gear
 
brianroth's Avatar
 
Joined: May 2005
Location: Salina, Kansas
Posts: 2,180

brianroth is offline
I am still curious if the noise is heard with merely a guitar plugged into an amp in the room, with no other connections involved for this test.

Best,

Bri
#8
28th April 2010
Old 28th April 2010
  #8
Lives for gear
 
Joined: Sep 2004
Location: UK
Posts: 6,768

Matt Syson is online now
Hi
Certainly in Europe the methods of safety grounding are very explicit in what is not acceptable. While technically it may 'ground' it in your instance there is nothing to say a change of pipework won't make the whole thing potentially 'live' if there was a fault.
Labelled safety earth straps to tie water, gas and electical circuits which must have labels and an established 'pattern' so other trades can understand the system.
Matt S
TC5
Thread Starter
#9
28th April 2010
Old 28th April 2010
  #9
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Quote:
Originally Posted by brianroth View Post
I am still curious if the noise is heard with merely a guitar plugged into an amp in the room, with no other connections involved for this test.

Best,

Bri
I don't have an amp handy but plugging a guitar in a mackie 1202 mixer yields about the same amount of noise as when I'm going through the rest of the setup.
TC5
Thread Starter
#10
28th April 2010
Old 28th April 2010
  #10
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Quote:
Originally Posted by Matt Syson View Post
Hi
Certainly in Europe the methods of safety grounding are very explicit in what is not acceptable. While technically it may 'ground' it in your instance there is nothing to say a change of pipework won't make the whole thing potentially 'live' if there was a fault.
Labelled safety earth straps to tie water, gas and electical circuits which must have labels and an established 'pattern' so other trades can understand the system.
Matt S
I'm in Canada so I'm not sure what the rules are here but I imagine they're quite similar. I tested the outlet with a little ground tester and it seems ok at least.
#11
28th April 2010
Old 28th April 2010
  #11
Lives for gear
 
Joined: Jan 2010
Posts: 890

Dubai is offline
Lightbulb

if its Ground loop hum, get Balanced Power.

Equitech Q
BPT
Furman IT
Monster Pro 7000
etc...

www.thecableco.com
etc...

or...
try bi-directional ground filtering power conditioners like:
Leveler RP24004A

i like more PS Audio Power Plant Premier, but... for ground loops
....most houses have a 3-phase 120v main.
use the best line, and use it exclusively for your audio equipment,
the lights can go to the other phases,
instal a long ground copper bar in the ground, with good copper wire and rewire your studio AC plugs.

buy good shielded power cables.
etc...

the Farady Cage isnt a bad idea.

another option would be Isolation transformers, like Eaton Power-Sure T800.
__________________
but if you cannot hear the difference:
Coup de grâce - Wikipedia, the free encyclopedia
Seppuku - Wikipedia, the free encyclopedia

commonly referred by the euphemisms:
"put to sleep," "to lay down," "to put down," "destroyed", "to put out of his misery," or "sent away to the farm."
#12
28th April 2010
Old 28th April 2010
  #12
Lives for gear
 
Joined: Sep 2004
Posts: 719

ripple_fx1 is offline
obviously, you want your mains power to be safe, but you can prove or disprove that it's the cause of your hum if you plug your mackie into a good UPC (unplug it from the wall once the battery is topped off) or inverter and make your own AC for a quick test.
TC5
Thread Starter
#13
29th April 2010
Old 29th April 2010
  #13
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Quote:
Originally Posted by Dubai View Post
if its Ground loop hum, get Balanced Power.

Equitech Q
BPT
Furman IT
Monster Pro 7000
etc...

www.thecableco.com
etc...

or...
try bi-directional ground filtering power conditioners like:
Leveler RP24004A

i like more PS Audio Power Plant Premier, but... for ground loops
....most houses have a 3-phase 120v main.
use the best line, and use it exclusively for your audio equipment,
the lights can go to the other phases,
instal a long ground copper bar in the ground, with good copper wire and rewire your studio AC plugs.

buy good shielded power cables.
etc...

the Farady Cage isnt a bad idea.

another option would be Isolation transformers, like Eaton Power-Sure T800.
Thanks for the info.

Might something as simple as this do the trick?:

PS Audio - Duet Power Center
TC5
Thread Starter
#14
29th April 2010
Old 29th April 2010
  #14
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
After doing a bit more reading, it looks like there's no cheap adequate solution to the problem (?) Equitec son of Q or PS audio power plant appear to be the cheapest options available... Unless the PS audio humbuster could do the trick?:

http://www.psaudio.com/ps/products/d...-iii?cat=power

Any ideas?
#15
29th April 2010
Old 29th April 2010
  #15
Lives for gear
 
Joined: Sep 2004
Location: UK
Posts: 6,768

Matt Syson is online now
Hi
STOP!!!
Get a proper electrician in to make the power wiring conform to 'specification'.
Talk of 'power conditioners' and whatever is simply ignoring the real problems if as I think was said earlier, that guitar amps (guitars) pick up hum.
A sugar pill won't completely restore a broken leg overnight, do the job properly.
Matt S
TC5
Thread Starter
#16
29th April 2010
Old 29th April 2010
  #16
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Quote:
Originally Posted by Matt Syson View Post
Hi
STOP!!!
Get a proper electrician in to make the power wiring conform to 'specification'.
Talk of 'power conditioners' and whatever is simply ignoring the real problems if as I think was said earlier, that guitar amps (guitars) pick up hum.
A sugar pill won't completely restore a broken leg overnight, do the job properly.
Matt S
So are you saying the house wiring may be a safety issue? Because as I read of balanced power etc. and this PS audio Power Plant module, it looks like all power coming from the grid is far from clean, hence noise and hum (in various degrees depending on location). If a module can take regular grid power and recreate a clean sine wave current from that isn't that safe?
#17
29th April 2010
Old 29th April 2010
  #17
Lives for gear
 
Joined: Sep 2004
Location: UK
Posts: 6,768

Matt Syson is online now
Hi
I am saying get it checked by a proper electrician and tested to electrical regulations.
Just joining a bit af water pipe 'somewhere' in a house does not suggest a safe installation as certainly in Europe the wire would start at the distribution board, NOT from a nearby pipe.
The makers of 'balanced power' and various 'conditioners' are SALESMEN who want you to BUY their gear, NOT the electricity company who have a legal duty to make sure installations are safe. The majority of power supplied to premesis is not as 'dirty' as the 'conditioner' folk would like you to believe and in any case would NOT produce major hum radiation which would make gear unuseable.
Quote: If a module can take regular grid power and recreate a clean sine wave current from that isn't that safe?
Unquote:
Safety is NOT the issue here, 'pure, clean sinewave power' will still kill you, but nicely, if it is not wired up correctly.
I have worked (as a technician) in many studios and very few have had need of 'power conditioners' simply because the mains is wired correctly. OK Indonesia had problems but the fact it went off for a few hours almost every day was the significant part.
Rather than wasting time on GS, get onto the local electricity regulations and read those, then if you don't understand it and you are not qualified to work on mains, get someone in who can.
Matt S
#18
29th April 2010
Old 29th April 2010
  #18
Lives for gear
 
2N1305's Avatar
 
Joined: Jan 2009
Location: Canada
Posts: 1,515

2N1305 is offline
I'd have to agree with Matt. It could be a safety issue. And all the more if you say it is an old house that had no grounding. For your sake (and others') call an electrician and find out if you have proper grounding on the outlets in that room, then ask him how much to get them properly grounded. Unless you are a licensed electrician, you cannot do electrical work in your home, unless you don't mind getting in trouble if something ever happens... this has been the regulation in Canada for the past couple of years, I believe. At least, in any new home being constructed, you will not get approved if the work was done by anyone than a licensed electrician.

If you must do it the "economical" way, I suggest you get a simple ground tester (get it at any Home depot or Canadian tire) and test those outlets. It's a simple go no-go LED tester that's simple to use.

If you're considering building a faraday cage, then it'd be a wise idea to redo the electricity in there before you enclose the walls in metal!
__________________
Not GerANIUM, GerMAnium, dammit!
TC5
Thread Starter
#19
29th April 2010
Old 29th April 2010
  #19
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Quote:
Originally Posted by Matt Syson View Post
Hi
I am saying get it checked by a proper electrician and tested to electrical regulations.
Just joining a bit af water pipe 'somewhere' in a house does not suggest a safe installation as certainly in Europe the wire would start at the distribution board, NOT from a nearby pipe.
The makers of 'balanced power' and various 'conditioners' are SALESMEN who want you to BUY their gear, NOT the electricity company who have a legal duty to make sure installations are safe. The majority of power supplied to premesis is not as 'dirty' as the 'conditioner' folk would like you to believe and in any case would NOT produce major hum radiation which would make gear unuseable.
Quote: If a module can take regular grid power and recreate a clean sine wave current from that isn't that safe?
Unquote:
Safety is NOT the issue here, 'pure, clean sinewave power' will still kill you, but nicely, if it is not wired up correctly.
I have worked (as a technician) in many studios and very few have had need of 'power conditioners' simply because the mains is wired correctly. OK Indonesia had problems but the fact it went off for a few hours almost every day was the significant part.
Rather than wasting time on GS, get onto the local electricity regulations and read those, then if you don't understand it and you are not qualified to work on mains, get someone in who can.
Matt S
Thanks Matt. I certainly don't profess to understand what's going on with the electrical wiring in here. The ground in this room was done years ago by an electrician. I can't tell if he was a GOOD electrician though...

There is also two wires coming from the electric distribution pole outside in the back that are coming right next to the (1st floor) window. I don't know if these are phone wires or not but I'm wondering if they're not causing some radiation in here being that I'm positioned close to that window.
TC5
Thread Starter
#20
29th April 2010
Old 29th April 2010
  #20
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Quote:
Originally Posted by 2N1305 View Post
If you must do it the "economical" way, I suggest you get a simple ground tester (get it at any Home depot or Canadian tire) and test those outlets. It's a simple go no-go LED tester that's simple to use.

If you're considering building a faraday cage, then it'd be a wise idea to redo the electricity in there before you enclose the walls in metal!
I did check the outlet ground with a tester from Canadian tire. Looks ok.

I certainly wasn't serious about the faraday cage though! I'm only here in this house temporarily.
TC5
Thread Starter
#21
29th April 2010
Old 29th April 2010
  #21
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
OK I did this test. Plug in a guitar in a duet into a Macbook pro running on battery. Duet is powered from the laptop so no grid power is involved. Hum and buzz about the same. What can I deduct from that? Radiating electrical interferences? Tried two different cables from the guitar. Same thing.
#22
29th April 2010
Old 29th April 2010
  #22
Lives for gear
 
Radardoug's Avatar
 
Joined: Oct 2009
Location: Northland New Zealand
Posts: 554

Radardoug is offline
Hi, You've just discovered what an electric guitar pickup is, namely a coil of wire in a magnetic field. What this test tells us is that a/ you have a strong magnetic field there, b/ the pickup is not a humbucker or is a bad design humbucker. Do you live by any large electrical installations? Have you always picked up this much hum? What has changed in your immediate physical environment?
#23
29th April 2010
Old 29th April 2010
  #23
Lives for gear
 
Joined: Jan 2010
Posts: 890

Dubai is offline
Exclamation

Quote:
Originally Posted by TC5 View Post
OK I did this test. Plug in a guitar in a duet into a Macbook pro running on battery. Duet is powered from the laptop so no grid power is involved. Hum and buzz about the same. What can I deduct from that? Radiating electrical interferences? Tried two different cables from the guitar. Same thing.
try another usb/firewire cable
then... another duet
or another mac

if else fails... the faraday cage.

probably its lots of RFI.
http://en.wikipedia.org/wiki/Radio_f...y_interference
or a damaged duet (broken/unsoldered ground)
or damaged instrument.

can you upload some .mp3?
#24
29th April 2010
Old 29th April 2010
  #24
Lives for gear
 
Joined: Sep 2004
Location: UK
Posts: 6,768

Matt Syson is online now
Hi
No No No!!!
You have now proven (with the guitar) that the electrical mains wiring in your house is not what it should be.
GROUNDING is actually another issue and is to do with SAFETY. Hum radiation from cabling is what I said a couple of days ago, the live and return current are following different PHYSICAL paths in your house for some reason. It COULD be that 'Neutral' has a fault to earth which would not necessarily cause a problem with fusing or even safety, as long as the grounds are and stay connected.
I was involved in installing a desk at Abbey Road many years ago and there was an 'intermittent' hum problem which was eventually traced to a power socket 3 floors up from the studio I was in having it's neutral joined to ground by the screw in the socket plate. As Neutral is usually joined to ground in many installations AT THE DISTRIBUTION BOARD it apparently caused no real safety problems but when power was taken from that socket some of the neutral current actually flowed through a 'steam pipe' that was correctly earthed but obviously followed a different physical path to ground.
A 'ground tester' will tell you it has a ground of some sort and is at present probably 'safe' but your hum problem is telling you that you have either a strong hum field from an external source (possible but not so likely if your house is on it's own) or you have poor wiring practice.
Matt S
Matt S
TC5
Thread Starter
#25
29th April 2010
Old 29th April 2010
  #25
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Thanks all.

Here are more details on the electrics in this house. Years ago the ground wire to pipe was put in in this room. Then a few years after, electric heating was installed throughout the house. A new mains circuit panel was installed at that time. I guess this might have been when the electric system could have been messed up somewhere. Could those electric heaters be a source of radiating hum and noise?
#26
30th April 2010
Old 30th April 2010
  #26
Lives for gear
 
Joined: Sep 2004
Location: UK
Posts: 6,768

Matt Syson is online now
Hi
Turn them off and on and listen for any differences then it will give you an idea if they are part of the problem.
Matt S
#27
30th April 2010
Old 30th April 2010
  #27
Lives for gear
 
brianroth's Avatar
 
Joined: May 2005
Location: Salina, Kansas
Posts: 2,180

brianroth is offline
To elaborate on Matt's last post, it is possible there is a "noise generator" within the house or nearby.

One trick is to use a battery operated radio capable of receiving the AM radio band, and tuning that radio down to the very low end of the AM band....in the range of say 540 to 640 kHz....where there are no local broadcasts to be heard. You will probably hear some "racket", but if you hear a loud screaming buzz across the unused frequencies, there is a local noise source.

Years ago, I made a service call to a studio which had been in operation for years and they began hearing a low, but obnoxious, buzz in multiple pieces of gear. The obnoxious buzz would begin ramping up in volume, then suddenly quit, only to repeat again, almost like clock work.

I went to my car in the parking lot, and tuned the radio to...maybe 600 kHz AM...an unused channel here. I heard the same "noise pattern"!

Walking around that studio building, I discovered a (mercury vapor?) security light on the building that was struggling to illuminate, even though it was broad daylight. Apparently the photocell had failed AND the lamp/ballast/whatever was also defective. Every 30 seconds or so, the security lamp "struggled" to light-up, then abruptly shut off.

That was acting as a noise generator which radiated into the audio system. As a quick fix, I disconnected the security light from the AC mains, and told the studio's manager to call an electrician to repair the fixture.

Bottom line...the AM radio test gave me a BIG clue.

Beyond that, always be sure your entire AC mains wiring is totally correct, and up to "Electric Code" requirements. "Ad-hoc"/random ground wiring and ground rods are both dangerous, and can contribute noise.

In addition, the June 1995 AES Journal has the MUST READ articles regarding this important subject. See:

AES Special Publications: Journal Issues

Reprints are $10 to Members (like me <g>), or $15 for non-members. Money well spent, IMHO.

Best,

Bri
TC5
Thread Starter
#28
30th April 2010
Old 30th April 2010
  #28
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Thanks Matt and Brian.

I will do the tests and see what comes up.
TC5
Thread Starter
#29
30th April 2010
Old 30th April 2010
  #29
Lives for gear
 
TC5's Avatar
 
Joined: Oct 2003
Location: North of indecision
Posts: 557

Thread Starter
TC5 is offline
Brian I've done a test with a small am radio. In the room where I'm setup there is a lot of noise at around "53" AM radio when I move out of the room the noise goes way down. If I move the AM dial all the way down below 53 the noise sounds a lot like a modem signal. A neighbour's (or my own) internet signal?

How does wireless broadband signal affect audio systems? I turned airport off my Macbook and the noise still remains.

Ok if I put my laptop to sleep the screaching stops. Still noisy but a lot less...
#30
30th April 2010
Old 30th April 2010
  #30
Lives for gear
 
brianroth's Avatar
 
Joined: May 2005
Location: Salina, Kansas
Posts: 2,180

brianroth is offline
Dear TC5,

With the laptop switched off, do you still notice a big noise difference on the AM radio as you leave the control room?

If so, what is adjoining the control room?

As for Wifi systems, they shouldn't cause noise to be injected into the audio system (unless there is a defect in the unit). I see Wifi stuff all over many studios.

Best,

Bri
New Reply Submit Thread to Facebook Facebook  Submit Thread to Twitter Twitter  Submit Thread to LinkedIn LinkedIn  Submit Thread to Google+ Google+ 
 
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
kamiahmed / The Moan Zone
9
GS Media / Video Vault
0
Dog_Chao_Chao / So much gear, so little time!
6

Forum Jump

SEO by vBSEO ©2011, Crawlability, Inc.