Ground Loop Hum or Guiatar Noise?

[blueflamez]

I play in a acoustic duet in a bar. I am using a fender 150W PA head to run our sound. Before a few weeks ago, everything was sounding good until the owners installed some neon lights and other junk near to where we play. I plug my acoustic Takamine into 3 effects pedals, powered by a 1spot, and from there straight into the PA head.

 

I am getting a bad hiss/hum from my guitar signal that wasn't there before. It gets louder when I turn on my ibanez chorus pedal as well. My guitar is the only signal input that is making the noise, there is no hum when the volume is turned down on the guitar or the PA channel. The other guitar/mics dont contribute to the problem either.

 

Now my question is this: is this possibly a ground loop problem with the power source? Why would my guitar all of a sudden start making interference/hum noises? Is it a coincidence that these new neon lights happend to be installed around the same time the problem started? Turning off the lights improves the sound some, but not much. Should I buy a boss noise suppresor or get a HumX or something similar for the power line?

 

Thanks for your input guys!

[agedhorse]

What model Takamine preamp do you have in the guitar? I assume it's a factory installed model.

 

Most likely... it is interference being picked up by either the piezo-electric element or possibly via inadequate shielding of the instrument cable to your amp.

 

Neon discharge lighting radiates a strong electromagnetic AND electro-static interference field, so it may not be solveable in any conventional or even suitable manner. Does the noise go away when the neon is shut off?

 

The first thing to try is a high quality instrument cable with a braided shield, or in this case even a double-braded shield may be necessary. Impedances are pretty high, so that may be a big part of your problem and it's not easily solved.

[ashivraj]

Does the buzz persist even if the pedals are run on batteries?

 

Does it persist after the Ibanez chorus is completely taken out of the loop?

 

Does it reduce if you turn down the output volume on your guitar's electronics?

 

AS

[karlw]

Sounds like it is not a ground loop but a loss of shielding inside the guitar, possibly between the pickup and the electronics. I say this because you indicate that when you turn down the guitar volume, the problem goes away. This right away eliminates everything after the guitar. It may be a coincidence that the hum seems to have started when the neon lights were installed. My guess is that something came loose in your guitar, such as a ground wire or possibly a shield. A good guitar tech should be able to solve the problem pronto.

 

-Karl

[Dogoth]

Electrostatic noise is much harder to deal with than electromagnetic noise (and yes neon lights tend to radiate a lot of both). If it's a low 60hz sound it's probably electromagnetic but if it's a Buzz (lots of high freq harmonic content), it's probably electrostatic. Try pluging another electric guitar (something with a pickup) into your rig and see if you still have the problem (since you said that turning down the volume of your acoustic makes the problem go away, it's probably in your instrument). One of the best thing you can do to help with this kind of situation is to use good quality cables with GOOD shielding and to keep all of your cords ar short as possible (sometimes a wireless setup can fix this problem by eliminating that long cord to your guitar).

 

Also poorly installed neon can wreak havoc with audio. I work in a place where they used to have a lot of Neon and if there was any arching at all (outside of the lamp its self), even inside of the rubber boots we would experiance terrible buzz problems. Please note that Neon operates at VERY HIGH VOLTAGES. DO NOT try to repair this stuff youself. Call a qualified electrician (we did).

 

Good Luck

[agedhorse]

 

Originally posted by JRBLE Electrostatic noise is much harder to deal with than electromagnetic noise (and yes neon lights tend to radiate a lot of both). If it's a low 60hz sound it's probably electromagnetic but if it's a Buzz (lots of high freq harmonic content), it's probably electrostatic. Try pluging another electric guitar (something with a pickup) into your rig and see if you still have the problem (since you said that turning down the volume of your acoustic makes the problem go away, it's probably in your instrument). One of the best thing you can do to help with this kind of situation is to use good quality cables with GOOD shielding and to keep all of your cords ar short as possible (sometimes a wireless setup can fix this problem by eliminating that long cord to your guitar). Also poorly installed neon can wreak havoc with audio. I work in a place where they used to have a lot of Neon and if there was any arching at all (outside of the lamp its self), even inside of the rubber boots we would experiance terrible buzz problems. Please note that Neon operates at VERY HIGH VOLTAGES. DO NOT try to repair this stuff youself. Call a qualified electrician (we did). Good Luck

 

 

Yes, correct.

 

Sometimes it's impossible to effectively shield against such a strong field. I'll bet radio reception is also affected;)

[blueflamez]

Any further insight?

[agedhorse]

 

Originally posted by blueflamez Any further insight?

 

What preamp is installed in the guitar and is it a factory installed preamp?

[madjack]

It may be a foolish comment considering the background of some of the posters on here, but does the hum lessen if you turn the guitar in different directions? I've played some places with single coil pickups that had horrendous hum which subsided somewhat as the pickup was moved in different directions. Double-coil pickups greatly reduced the hum problem.