noise from electricity (guitar)

[gordon_freeman]

I have an average guitar, and 50 Hz noise drives me crazy, is there hardware/software which helps to reduce the noise? I mean, that one which happens because of AC (or is it DC?)... well, elecricity waves produce it.... Buying a new better guitar is not a solution to me though... hehe....

[rogerperrin]

Tell us what kind of setup you have and we can better isolate and diagnose the hum problem - could be a bad ground on guitar or anywhere, bad capacitor in amp, playing too close to a crt or TV?

[metalsvinet]

I'm assuming your guitar has single coil pickups, but that you don't intend to change it. In which case:

1. Turn off your monitor if you're close to it.
2. Shield the insides of your guitar with metal foil or paint, check all connections and use good cables.
3. Realise that noise is your friend. Use it creatively.

[IainF]

50hz is very close to the note of 'G'. You could play everything in 'G' and then it would be in tune.

[C00kie]

Any "notch" filter can be used to filter it out, but there is something causing it. Best is to cure it at the root.

Does it help if you aim the neck at the PC monitor? Then see what happens if you turn off the monitor. The guitar pickups will pick up humm from TV sets or PC (crt) monitors.

It also can be a faulty cable, or a weird phenomena called "ground loop" (electricity running in circles through the ground wires)

If you tell us more how you have connected the guitar into the PC, that will help.

For instance if you have plugged it directly into a mic input, then that explains it. The mic input is too sensitive so just a bit of hum (it's always there) gets amplified.

Also what you do with it inside the PC matters. Suppose you have a clean guitar signal with just a tiny bit of hum. Then put it through a distortion effect, and the hum will be overwhelming.

Best is to then use a noise gate or notch filter.

[greendoor]

AC hum/buzz in guitars is a nightmare of a problem, if you are at all interested in quality quitar tone. It can come from many different sources, and very few people understand them all. On the internet, you will get a lot of information, and some of it is helpful and some can be misleading. People who don't have your particular problem can often have no understanding of the cause or solution. Some people are lucky to have clean AC power and good grounds and live in a relatively benign EMI environment. Why do you think the truely great studios tend to be rural or on islands and stuff? It's not all about tax evasion ...

I've spent a lot of time and money trying to solve my problems, and it hasn't been easy.

My ideal guitar room would be so free of EMI that you could take a budget strat-shaped object with no shielding, and it could be recorded with zero hum. That's actually a possible goal: you don't need shielding unless there is something to be shielded from.

But, with todays switching power supplies and cell phone towers and who knows what, you would be struggling to get this immunity in most places.

You can build faraday cages if you want total isolation. But it's probably more practical to build the shielding into your guitar - starting with quality guitar cables. I'm appalled at the lack of quality guitar cables - my expensive Planet Waves cable is an absolute joke.

Learn the difference between electromagnetic and electrostatic emi. Basically, it's the difference between current and voltage. A steel box or ferrite beads constrain magnetic flux - but electrostatic emi is channeled by steel conductors. Electrostatic EMI can be stopped with grounded aluminum foil - but magnetic EMI goes right through aluminum.

Get a little cheap battery amp. Using a short lead, this becomes an excellent electrostatic emi detector. You can trace emi fields - you may be surprised to find that electrical fields are streaming down buildings and all sorts of wierd things.

If you plug a guitar pickup (like a Woody single coil pickup on a lead) you can use the amp to trace electromagnetic hum - which is very different, but often related to the same sources.

DC is your friend. Consider DC lighting if necessary.

But all your efforts to solve AC hum/buzz are in vain if you have AC currents on your electrical ground. In practice, electrical ground is connected to Neutral, and is dirty as hell. At my place, I can connect an 8 ohm speaker between electrical ground and a spike driven into the ground (just a hunk of aluminum channel) and I can drive that loudspeaker with a very loud buzz. It measures 1.5 volts AC at my place - and I suspect this is not uncommon these days with switching power supplies and fluorescents being increasing used. This stuff varies day and night (as your neihbourhood switches stuff on/off).

That crap on your electrical ground is what is connected directly to the "shield" on your guitar cable. There is no wonder that many guitar amps buzz.

If you drive a ground spike into your ground, and connect it to the electrical ground, what tends to happen is that more of this crap gets diverted to your place. Tracing this with an emi detector can be very surprising!

At some point you will find that there is a tension between legal electrical wiring and suitable audio engineering. The great studios have all solved this dilema, one way or another. Safety has to be paramount - so i'm not going to tell you how it's done. But there is some great information at www.equitech.com that might help.

Your problem might be a lot simpler - also experiment with snapon ferrite beads on leads.

[gordon_freeman]

Thanks guys...

Well, I plug my guitar to FX pedal, then into EMU 0404 audio card, usually I use the pedal just like a preamp (I use GuitarRig to overdrive mostly). If I plug out my guitar I still hear hum (that's the word I didn't know )) but much less than with guitar, I believe it's pedal producing, but the itself pedal noise level it pretty low. I'm sitting right near the PC, but when I'm trying to stay somewhere else with guitar in the room, noise is still here (although the level of it changes a bit).


>3. Realise that noise is your friend. Use it >creatively.

haha, cool idea, but seems not my solution... ))

>2. Shield the insides of your guitar with metal >foil or paint, check all connections and use good
>cables.

well, that's makes sence... it's what I will try soon, thanks.

>It also can be a faulty cable, or a weird phenomena >called "ground loop" (electricity running in >circles through the ground wires)

thats definitely caused by wires inside walls, but I'm looking not for the reason of noise, but the soulution how to reduce it )) I had crazy Idea to isolate walls in my room with wires or foil, but my father (he's electrician) said it's useless... ))

Yeah, noise gate removes noise in pauses, but sound still it dirty when gate is switched off at useful misical signal... seems like that.

Filtering: I tried to reduce the noise with EQ but found this noise has basic harmonic on 50 Hz, but it's not just sine and lays over the entire spectrum... btw, found some strange and cool way to kill the noise (if set a flanger depth, rate and feedback to zero, set "invert wet" and find very carefuly delay time which knocks down any periodic noise, but it knocks down huge useful part of musical signal as well, and makes delay-like effect, so I cant overdrive it.... ) I tried some noise removing plugins, but these didn't work well, sometimes no noise - but no good sound again, it kills guitar spectrum, too....

[greendoor]

You are correct that gating is not the answer. Gating only hides the problem when you are not playing - completely useless and compound the problem. The gate is wide open when you are playing, and those hum/buzz freq's will beat against your notes and everything just sucks. If you are lucky to have 50 or 60Hz hum, that can be filtered out. But buzz can fill up the entire frequency range, and it's impossible to remove. Prevention is the best cure.

Get your dad to read the techy articals at www.equitech.com - it's strange science to most sparkies, but note that the successfull studios have al solved this problem very well. You don't have to live with hum, and there is nothing nice or creative about it.

[P.T.]

If your amp has a 2 prong plug try reversing the plug in the socket.

It's possible that the noise source is a neighbor with flouresent lights or something. Nothing you can do about that I guess.

If you are using single coil pick-ups maybe a pair of noise cancelling single coils would help.

[gordon_freeman]

50hz is very close to the note of 'G'. You could play everything in 'G' and then it would be in tune.

hehe, should I change my nick name to G-Man?? (for those who understand ) Good hint!

2PT - yep, this makes sence too, noise is the same on two cables, one has useful signal other just noise, inverting one of them and summing with another could give a good result... Gotta plug something to my second Sound Card input and try it....

[AndrewSimon]

It's possible that the noise source is a neighbor with flouresent lights or something. Nothing you can do about that I guess.

You can completely eliminate this by using a balanced AC power system but it's expensive.
I built one myself but it was still quite expensive.
More info here:

http://www.kvraudio.com/forum/viewtopic.php?t=93443

Please note this system will eliminate everything that comes down the power line.
It does NOT eliminate other noise sources that you pick up in the studio but it helps to quite them as well if you use balanced power exclusively throughout the studio.