Grounding issues

[Oreomeister365]

The eternal buzz is bugging me.

I have a keyboard and a line in from the bass running to the mixer. Listening directly from the mixer. Keeping the keyboard on mute, If I press the gnd button on the line in of my bass amp, no noise, as soon as I unpress it it, a lot of noise (high pitched frequency)

I unmute the keyboard on the mixer.

The noise is back. But press the gnd button on the bass amp, the volume on the high pitched note decreases, but is still there.

I daresay I'm having grounding issues.

Now, the bass is going from the line out of the amp into the mixer via xlr cable, whereas the keyboard is going from a 1/4" output on the back of it to the mixer.

I suppose it could be the method of my connecting fromt he keyboard? perhaps a cable somewhere?

Is it possible to ground everything in such a way that it will eliminate all potential sources of noise? This is quite a nuisance, and I know next to nothing about grounding and what could potentially make it cause noise.

Thanks in advance, all help is appreciated.

 

[fokof]

Very bad idea and dangerous to remove the ground from everything.

Try to isolate the source of the ground loop.
-plug your bass directly in the mixer , bypassing your amp.
-Try a Pin 1 lift on the XLR.
-Then , try an electrical ground lift , even if you have one on your amp.

Then try to ground lift everything but one at the time.

Don't forget that some equipement are more sensible to electrical noise.
If you have a fridge , cooler , electrical motor of some sort on the same circuit , it can also be the source of the noise.

Good luck

 

[seamonkey]

Some info in this article:
http://www.soundonsound.com/sos/jul05/articles/qa0705_1.htm

 

[Bottom Lover]

Is all your gear plugged into the same AC outlet? If you have gear plugged into different AC outlets you will get a ground loop that will cause the symptoms you have described. Get a high quality line AC conditioner like a Furman or a Monster and plug ALL your gear into that.
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[fokof]

If you have gear plugged into different AC outlets you will get a ground loop that will cause the symptoms you have described.

Usually there is only one electrical panel in a house or an appartement.
Two different circuits will go to the same panel , sharing the same ground.

 

[Oreomeister365]

Thanks for the replies, working on it.

 

[bassbrad]

Problems you describe can come from several sources, the most common would be a false ground, polarity switched, EMF or connectivity issue. The often overlooked source of noise in a studio is a connectivity issue or choosing the right cable and I suspect that is where your particular the problem lies. Connecting the line out from the amp and the line out from the keyboard may be causing a polarity issue between the signals. 1 the amp may be overloading the input on the mixer many line outs are designed to run a power amp or other professional device at 1 volt and many mixers have problem handling a full volt. the cable you are usung may also be an issue, try another solution there. 2 The connection from the keyboard may be a stereo or trs connection try both a trs/trs or a trs/2x 1/4. False ground or a switched polarity is very common and can easily be with an inexpensive outlet tester available from any hardware or home building supply store usually less than 10 bucks. If you find a wiring issue it can be easily resolved by correcting the fault. I also keep one of these in my gig bag to detect faulty circuits at gig.
EMF ElectroMagneticFields are also a common source of noise and can come from several sources. Most common are neon lamps, TV or CRT screens, in many cases those only need to be removed from proximity. The less common line noise or dirty electricity or interference from another appliance like a TV, refigerator or other large appliance here a line conditioner may be a solution.