Buzz When Running Amps in Stereo

[Pink Unicorn Horsey]

I have two amps that I like to run in stereo: a Vox AC30 and a Fender Super Reverb (both reissues). The way I run it is by plugging my guitar into a few effects, then into the left input of a Line 6 DL4 Delay Modeler. The DL4 has stereo outs, so I run the left output to the Vox and the right output to the Fender. The problem is that I get a loud hum from the Fender and an even nastier hum -- more of a buzz -- from the Vox.

Here's some more info for you amp gurus:

• Each amp is plugged into the same power strip.
• I get the hum/buzz even if I skip all the other effects and go from guitar to the DL4 then out to the two amps.
• Although more pronounced when both amps are turned on, I'll still get buzz from the Vox if the Fender is turned off, and I'll still get hum from the Fender if the Vox is turned off.
• The only way to get rid of the hum/buzz is to turn off one of the amps and unplug the lead going from the DL4 to that turned-off amp. (I can leave the jacks plugged into the DL4, but I have to unplug the input jack to whichever amp I'm turning off.)

What gives? Is there a way to run these amps in stereo without getting the hum/buzz -- The Huzz?

- Keith

 

[BigDaddy]

Re: Buzz When Running Amps in Stereo

Make a guitar cable with the ground cut at one end and run that to one amp. You have a ground loop. There are some new devices that can lift the ground at the wall and is safe as far as I know. You will have to google that. But your problem is a ground loop.

 

[lpmarshall]

Re: Buzz When Running Amps in Stereo

Here is one thing to try, plug the amp power cables into different outlets in the wall. This is more of a test and not a permanent solution.

There are some products such as the Ebtech Hum Elimintor and a product by Morley that are designed to eliminate this hum, I believe. Isolated outputs usually fix the problem.

 

[jeremy]

Re: Buzz When Running Amps in Stereo

i ran two amps quite a bit. basically you need to lift the ground on everything but one amp, including any fx which isnt a big deal since most only have two prong adapters. the easiest way is to use a three prong to two prong adapter.

while youre at it, you might check the phase of the amps to make sure they are working togeather, not against each other

 

[Pink Unicorn Horsey]

Re: Buzz When Running Amps in Stereo

i ran two amps quite a bit. basically you need to lift the ground on everything but one amp, including any fx which isnt a big deal since most only have two prong adapters. the easiest way is to use a three prong to two prong adapter.

My understanding was that two-prong adapters are a no-no.

 

[jeremy]

Re: Buzz When Running Amps in Stereo

you have a ground loop, thats whats causing the noise. as long as you have one amp grounded its ok, its good to be cautious when plugging in and unplugging everything, meaning hitch everything up before you plug anything in.

i learned this from a friend who went to gerald webers amp camp or whatever he calls his seminars and have been doing it for a while with no problems

 

[Pink Unicorn Horsey]

Re: Buzz When Running Amps in Stereo

I just picked up an Ebtech Hum Eliminator off eBay. That should do the trick.

Thanks for your help, everyone!

- Keith