Noise Noise Noise!!!!!! How do I get rid of 60Hz hum?

  • Thread starter Thread starter nemal
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nemal

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I have a Layla IO for my computer. When I hook up my synth, drum machine and mic (through a Focusrite preamp) to it and have the analog output routed to my Yamaha ProMix01 everything sounds fine. But when I hook up my Line 6 AX2 212 guitar amp outputs (which are designed to drive a line in) to the layla I get a lot of noise. 60 Hz hum I believe.
It doesn't matter what I do with the amp, turn it down or turn it up, the noise stays the same. If I turn the amp off, most of the noise goes away. The amp is new. So I must have a ground loop, or not a good ground at all. I'm sure this is a basic problem for the experienced engineer, but I am a mere mortal. Can anybody give me some advice.

Thanks,

Nemal
 
try a di

maybe u should try and use a di(direct injection box)
and see if it helps...

this should help... i think
 
sorry... forgoten something

u should also use the same power point u use for ur other
equipment, also known as a star point power supply.. or something like that

this could cancel out the ground loop.. it might help or it may not
 
Look for a ground lifter at your local electric shop.
This is an adapter that will receive your 3 prong from a standard AC cable but turns your ground pin into a tab.
Ask at your shop how to properly hook it up. It's quite simple.

You can also try this -Disconnect your shield at one end of your cable. This will break the ground loop. Just open the connector and cut (or unsolder) the braided shield from the lug it's connected to.


WARNING !!!!! - If you touch Equipment that isn't properly grounded and you
are standing on the ground, you become the path to the ground
that the Electricity is looking for !.

If you are serious about your studio then it's well worth the money to hire an electrician who's expertise is studio grounding.

Good Luck
 
I posted a blurb on star grounding in another thread:

https://homerecording.com/bbs/showthread.php?threadid=18193

Since I posted that, I also stumbled across a couple of very nice white papers by the president of Jensen Transformers on hum rejection in single-ended systems (I'm new to this web search stuff). He and I disagree on a few points, primarily because his focus is on selling transformers, and mine is on building studios for very little money. However, his analysis is impeccable, and he does an excellent job of educating people on the "whys" of hum and ground loops. Check out these URLs for a slightly different viewpoint:

http://www.jensentransformers.com/an/an003.pdf
http://www.jensentransformers.com/an/an004.pdf

He and I will just have to agree to disagree, but I highly respect his points and urge everyone else to consider them. However, I still prefer to do my own job of grounding, using the time-proven star scheme, and relying on transformers only when I can't possibly avoid it- because the damned things cost money, and a properly-executed star grounding scheme is essentially free, in use in a great many pro studios, very safe, and very reliable and quiet...

Hope that helps!
 
This are the things I have noticed can help for hum:

Some power cords have contacts wich you can put in two ways, as opposed to the american grounded connectors, which only fit one way. (In Sweden, they ALL are possible to put in two ways). Turning them over, one by one, can reduce hum.

Turn all unused equipment off. Especxially flourescent lights have a tendency to add hum. (If this is through magnetic fields or trough creating ripples on the power I don't know.)
 
software eq like cool edit and others

Any parametric eq can notch out that 60Hz buzz.Make the "Q" about 6 cycles wide centered on 60Hz and cut 20 dB.Previous advise about grounding is good.But unless you live in a faraday cage like Gene Hackman in Enemy Of The State,you are gonna have grounding problems.As much as possible run everything in the studio off the same circuit.No flourescent lights,etc.
regards
Tom
 
Here ya go!

Try a whirlwind direct box with a lift/ground switch. Just flick the switch to ground and the hum should go away.

-sondriven
 
hum

make sure your audio cables are away from your power cables if they must touch try to cross at right angl.es instead of going along side of each other
 
you can also use a plugin eq and stack about 4 bands on 60 hz or the offending frequency
 
Re: software eq like cool edit and others

Tom Hicks said:
Any parametric eq can notch out that 60Hz buzz.Make the "Q" about 6 cycles wide centered on 60Hz and cut 20 dB.Previous advise about grounding is good.But unless you live in a faraday cage like Gene Hackman in Enemy Of The State,you are gonna have grounding problems.As much as possible run everything in the studio off the same circuit.No flourescent lights,etc.
regards
Tom
Click to expand...
Tom's right - parametric EQ *can* help - but it then becomes a trade-off between introducing phase problems by using the EQ vs. hearing the hum... fixing ground issues will be the more effective of the 2 solutions.

Bruce Valeriani
Blue Bear Sound
 
Here are a bunch of other good pages for education on chasing noises out of your rig. I just discovered this resource, and it is going to save me a lot of typing in the future...

http://members.nbci.com/studio_tech/links.html

Look down the page for "Wiring and Grounding". There is a vast amount of Good Stuff here: this is Scott Holderman's "Studio Maintenance" page, and a lot of the links should be considered required readings...

Ah jes' _love_ it when somebody else has already done all the typing.
 
To be sure that you have a ground loop, put the mixer and the amp in the same outlet and have NOTHINg else plugged in. If it still hums, it's not a ground loop.
 
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