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Humming and Buzzing Problems


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[b]Humming and Buzzing Noises[/b]

There are many possible causes for humming or buzzing noises from your amplifier. The key to resolving this problem is to be methodical and eliminate each possible cause one after the other. The following will guide you through the basics.

[b]Is There A Problem At All ? [/b]

Firstly you should work out if there is actually anything wrong with your gear or if the noise is to be expected. All bass guitar pickups will be affected to some degree by strong electromagnetic fields in close proximity to the guitar.

Move around the room with the guitar. Does the noise lessen or disappear as you move around ? If so then there may be some “noisy” electrical equipment in the room. Some common culprits are –

1. Computers screens and computers
2. Fluorescent and “low-energy” light fittings
3. Lighting dimmer switches
4. Cheap mains transformers (e.g. pedal power supplies)
5. Fridges and air conditioning units

If you suspect there is some noisy equipment then try switching the equipment off to eliminate that as the cause of the problem. If you cannot switch off the equipment then move it away from your gear (or you gear away from it), to where the noise disappears.


[b]What’s Changed ? [/b]

Next, think about the problem. Are you using gear that has been OK until now and the noise has just started ? If so, have you changed anything immediately prior to the noise starting ? Have you added a new FX pedal to your setup ? Are you using different cables ? Are you in a different room ?

If so, try to “undo” this change to see if that has caused the problem.

Note that “noisy” electrical supplies can exist and that you may find a problem in a particular room, or building, that disappears when you play in a different location.

[b]Earth Loop In The Mains Supply [/b]

This sounds complicated but is quite simple and easy to check for.

Wherever possible, all of your bass gear should be powered from the same 13-amp socket in the wall. You should avoid, for example, plugging your amplifier into one 13-amp socket and plugging a pedal board power supply into a different 13-amp socket in another part of the room (a twin 13-amp socket is OK). You should also avoid running some of your gear from 13-amp sockets in one room and running other gear from an extension cable connected to a 13-amp socket in another room.

[attachment=83:HB1.jpg]

Check to see if this applies here. If it does, then try powering all of your gear from the same 13-amp socket in the same room, using a multi-way board if necessary.


[b]Safety First [/b]

Now that the problem is not immediately obvious you need to investigate further. Before doing so you should ensure your gear is SAFE. All that you can do here is check the 13-amp plugs on any power cables that are supplying your gear.

Unplug all your power cables and open up the 13-amp plug. Have a look inside and check that the plug is wired correctly (see image) and in particular that the green and yellow earth wire is connected to the top earth pin inside the plug. Check the screws on the pins are tightened firmly. If the plug is moulded on then try using a different power cable.

Below is a correctly wired UK mains plug (apologies if you're reading this from another country - I don't know the wiring regulations anywhere else but the same principle for the earth wire will apply).

[attachment=84:HB2.jpg]

Repeat this process for each mains power lead, and don’t forget to include any extension cables or multi-way adaptor boards that you are using. If you find any problems or any dodgy wiring then you should fix this immediately. If you don’t know how to fix it then find somebody who does. NEVER use power leads that are badly wired and NEVER remove the green/yellow earth connection from a plug.

[b]Simplify The Problem [/b]

Now try to identify the component causing the problem. Strip your gear down to basics – bass guitar plugged directly into the amplifier with no FX connected. If the problem is still there then it can only be the guitar, amp, or guitar lead (see next topic).

If the problem goes away then try bringing in any other items of gear (e.g. FX) one at a time and noting at which point the noise begins. If you can do this then you should be able to identify which piece of gear is causing the problem.

[b]Swap Gear to Identify the Problem [/b]

Once you have narrowed the problem down you should try swapping gear to eliminate the problem. Guitar cables can often be the cause of problems so try different cables to see if they are OK.

If you have two guitars, try each one to see if this makes a difference. If you have access to another amplifier, then try that. Note that you could try the bass through a guitar amp (quietly) to help see if the problem lies in the guitar or the amp.

[b]Noisy Guitar Lead [/b]

If it’s a cheap cable then throw it away. If you’re going to keep it then mark it so you know there’s a problem, otherwise it’ll come back to haunt you !

If the jack plugs are not moulded-on you could open them up and check for loose connections, fixing any problems that you find. You could even cut off the jack plugs and replace them but bear in mind that the problems may be inside the cable somewhere and it’s very difficult fix that kind of fault.

[b]Noisy FX Unit [/b]

If the noise is cause when an FX unit is added then look carefully at how you are connecting this unit. Are the leads used by the FX unit ok ? (try different leads). Are you connecting the unit correctly ? If the FX unit is in the Send/Return loop of your amp then check that this is configured correctly and that the FX unit is compatible with the FX loop.

If the FX unit is connected via an XLR cable (microphone rather than jack cable) then is there a “ground lift” switch anywhere ? Engaging this will often cure the problem. Alternatively, you can modify an XLR cable by disconnecting the ground wire from one of the XLR connectors – this will not affect the operation of the unit but can sometimes eliminate humming/buzzing noise.

Sometimes the mains power supply (wall-wart or power brick) can be a source of noise. Try getting someone to move the power supply while your gear is setup. If the noise varies as the power supply is moved then find a location that minimises the noise.

[b]Noisy Amplifier [/b]

If the noise is coming from the amplifier, and you have checked that the earth wire in the 13-amp power cable is OK, then you will need to have this checked out by someone competent.

NEVER open up an amplifier unless you know what you are doing.

[b]Noisy Bass Guitar [/b]

Some guitars are noisier than others – in particular those with “single coil” (i.e. most Fender basses) as opposed to “humbucking” pickups. Some degree of noise during gaps in music may be acceptable but it should not intrude on your playing.

Humming or buzzing noises from the guitar suggest problems with earthing or shielding inside the guitar. It is quite safe to look inside the guitar but you will need to have some idea of what you are looking for and be able to use a soldering iron to fix any problems. If this is not you, then find a competent friend or take the guitar to a repair shop.

Common wiring problems inside a guitar include –

1. Broken earth wire inside control cavity
2. Missing or broken earth wire from bridge to control cavity
3. Too many earth wires
4. No shielding (metal foil or screening paint) in control cavity
5. No connection between shielding and earth

Bass wiring varies enormously. If you suspect a problem with your wiring then search the net for a wiring diagram or ask on this forum for advice on how your bass should be wired.

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I have a epi nikki sixx blackbird, a white epi tbird and a les paul bass and i use a laney rb9 stack. recenltly i been getting an earth buzz from all 3 bass guitars, i've tried different cables and other amps in different locations but the buzz is still there sugesting it lies in the guitars does anyone have any ideas why all 3 should get this at the same time.

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[quote name='ianb696' post='294907' date='Sep 29 2008, 08:28 PM']I have a epi nikki sixx blackbird, a white epi tbird and a les paul bass and i use a laney rb9 stack. recenltly i been getting an earth buzz from all 3 bass guitars, i've tried different cables and other amps in different locations but the buzz is still there sugesting it lies in the guitars does anyone have any ideas why all 3 should get this at the same time.[/quote]

I was also trying to track down a similar buzz that was afflicting all guitars, all amps and all cables. Turned out to be the overhead lights downstairs that were on a dimmer switch.

If all three guitars seem to have acquired a problem simultaneously, then the problem is almost certainly not in the guitars.

S.P.

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Great post here - a bit of a must read for anyone!

I've sussed that my pedal is making a hell of a lot of noise - It's an 'Aria TD1 Platinum Drive Tube Distortion Pedal'

I've been using it for a while now with no problems at all, but in the last week a hell of a lot of 'noise' has been generated through my amp. I'm presuming it's the pedal, as when you change the level of it the noise gets louder/quieter.

What kind of faults occur in pedals, and what's the best way of getting them sorted!

Thanks,

Ben

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Copper shielding might help? My (passive) Jazz is now very, very quiet since I used low impedance copper foil throughout (got it on Ebay) - I also did find a major culprit was simply sitting too close to the amp - being three feet away rather than two made all the difference.

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Hey! I play an active cort g-series bass and when i play a low note (especially in drop-d tuning) a large fuzz comes through the amp, this happens when i play through other amps but not with other basses, and still occurs when i change the cable. I'm not sure if the problem is electrical or to do with the low action on the bass... Any ideas??

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  • 3 months later...

Just a thought for some people who have active basses.I thought I had developed a new buzzing fault on low notes,thought I had speaker problems ............................. turns out it was a battery about to expire!two new batteries later and it sounds as lovely as it ever did.

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Theres so many thing which cause 50 or 60 cycle hum, ground loops...

i wouldnt advise removing the earth socket for obvious reasons.

Make sure you have well shilded cabling and instruments first. Foil or conductive paint are great for the insides of your guitar for sheilding against hum.

Its pretty hard to avoid... single coils are usually worse for signal to noise ratio

Hope this all helps

jack

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A useful tip is to use a multimeter set to ohms (resistance) holding one probe on the earth contact of the output jack and the other probe on parts of the shielding or earthing to check that there is a good route to earth.
The closer to zero the number shown, the less resistance there is. This helped me to idenify several dry joints and also imperfect contacts between copper foil and earthing.

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[quote name='BarnacleBob' post='780810' date='Mar 20 2010, 02:38 PM']My Levinson Blade B3 is fine and quiet until it comes within a foot or so of whichever amp its plugged into (no effects)


Any Ideas.

BB[/quote]
I would expect it within a foot or so, more so if it has single cpil pickups.
Reviewing the shielding and earthing as discussed here and you might improve it a bit but basically just stand further

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anyone managed to cure this?

"directional magnetic pulsing" which can be caused by the transformers in amplifiers. apparently there isn't much that can be done about this apart from making sure that you are using a good lead and ideally keep your distance from the amp

only way i can stop it is to have the bass in a very specific position, sort of side on to the amp

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[quote name='allihts' post='456751' date='Apr 7 2009, 07:53 PM']Hey! I play an active cort g-series bass and when i play a low note (especially in drop-d tuning) a large fuzz comes through the amp, this happens when i play through other amps but not with other basses, and still occurs when i change the cable. I'm not sure if the problem is electrical or to do with the low action on the bass... Any ideas??[/quote]

Could be the action, but check/replace the battery in the Cort.

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I've got an Epiphone T-bird Pro IV which I haven't played for a few months. I had someone come round to look at it and it makes a buzzing/humming noise unless you have contact with the strings, or the bridge. I swapped cables etc and it wasn't plugged into any effects, so I'm not sure what's causing it. I replaced the 9v battery as recommended and it still hums!

Any ideas of what I can do to rectify this? Also, if in needs someone to look at it does anyone know anyone in Leeds?

Cheers guys!

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[quote name='omikin' post='987417' date='Oct 13 2010, 08:02 PM']I've got an Epiphone T-bird Pro IV which I haven't played for a few months. I had someone come round to look at it and it makes a buzzing/humming noise unless you have contact with the strings, or the bridge. I swapped cables etc and it wasn't plugged into any effects, so I'm not sure what's causing it. I replaced the 9v battery as recommended and it still hums!

Any ideas of what I can do to rectify this? Also, if in needs someone to look at it does anyone know anyone in Leeds?

Cheers guys![/quote]

I have the same bass and have exactly the same problem. I tried scraping the paint from the underside of the bridge where the earth cable contacts but it didn't change it much. I have an older Epi T-bird iv (not Pro) which I get no hum at all from even when using the same setup, cables, effects,etc. Any info would be most welcome. Ta!

Since originally posting this I noticed that inside the back cavity cover there were two wires ( a very fine red one from each pickup) had not been soldered onto the earth terminal of the lower left pot (as seen when looking from rear of bass). In fact both these wires had a rubber insulation sleeve over the ends of them. I removed this and soldered both onto the earth terminal of this pot and the hum has gone.[attachment=62749:100_3433.JPG]

Edited by t-bird-iv
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Sorry to open up the thread.

I have an aerodyne jazz. I have just installed Seymore Duncan quater pound on the J pick up. The the J pick up already buzzed a bit when it was full on with no P in the mix. After I installed the you SD, I noticed the buzzing stopped completely when I touched the bridge. I'm using Trybass strings, so just touching the strings doesn't work as the strings are coated with nylon

Any thoughts, I checked the earth goes to the bridge, but If I could grow an extra arm, I'd be fine ;-)

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