Amplifier buzz

[Ampacity]

Hello We are having a problem with a personal amplifier in our church. The sound tech normally puts a micophone in front of the guitarist's amp to add him to the mix. The guitarist complains that there is an annoying buzz in his amp which only disappears when the mic is muted. Any suggestions as to how we can correct our problem. Thanks in advance Tom

[RelativeMischief]

So the buzz is coming from the guitar cab? Is he using FX petals or any gear between the axe and the cab? A dirty in/output on any outboard gear could generate a buzz.

A bad ground in the socket he's plugged into. Highly doubt this one though.

Volume on amp is too high and volume on axe too low, try playing with the gains a bit.

Bad patch cord. (patch cord might be too long as well if he's using a TS cord)

Is there a florescent light or dimmer pack close to the amp? If so move the amp away.

Thats all I can think of off the top of my head. Not being a guitar player I couldn't tell you about any problems internally with the amp, someone else here probably can though.

[avkid]

what type of amp is it? certain types are supposed to be mic'd from the rear if the backs are open.

[SketchyCroftPpl]

We've had some trouble with that before cause the people just didn't push the connections into the amp enough. The amp may me making a very small amount of noise which the mic picks up and makes louder before it puts it out on the speakers. So maybe try varying the distance the mic is from the amp w/o losing any of the other sound quality?
~Nick

[Mayhem]

I had similar thought at first, bad connection, interference, ground hum etc, etc.

However, I am unable to think of anything that would tie the mic being used to mic up the amp causing a hum in the amp that is being mic’ed up.

I am assuming that it is not a radio mic that is being used which is interfering with the wireless system being used by the guitarist.

Perhaps a bit more information on the equipment being used would be more helpful and perhaps lead to an answer

[SketchyCroftPpl]

yeah ... also ... how is everything hooked up? is the sound from the mic coming out of the amp or external speakers .... we had people for our open mic who wanted all the mics out of their own amps ... which I think could cause a little bit of noise to built up and everything ... or is it that the person brought their own amp and them you guys hooked the mic upto the soundboard and put it out normally? Yeah I deff think we need to know more info about the setup and such before a problem can be defined.
~Nick

[Mayhem]

Placing a microphone in front of a guitar cabinet (or any other speaker) and then running that input into the same amp that is driving that speaker is just asking for trouble. In this scenario, it is not the hum or buzz I would worry about it is the feedback.

Also, different impedance between guitars and microphones add another dilemma to the equation.

[SketchyCroftPpl]

Yeah ... I realized that you probably would get more feedback than a hum but its the same general idea. We were having tons of trouble with out stuff for the show I was talking about. For one thing all of a sudden everyone in the audience could hear w/e we were saying in the booth which is just freaky cause there is no mic or anything in there and the headsets are on a seperate circut that can't be played out of the theatre's speakers so it was just strange ... and we had like 10 of the 20 sliders up cause over the night we had to be using spymics and 4 regular mics and aux and vcr stuff which there are two of and all that so it could have been anything.
~Nick

[soundman1024]

Sure it isn't a buzz coming through his monitor?

[mr_sound]

Originally Posted by SketchyCroftPpl

For one thing all of a sudden everyone in the audience could hear w/e we were saying in the booth which is just freaky cause there is no mic or anything in there and the headsets are on a seperate circut that can't be played out of the theatre's speakers so it was just strange

Some boards have a built in talkback mic. Is it possible the talkback was engaged and being sent over the main mix? Other than that, there's no other logical explanation for your problem.

As for the guitar problem....I've noticed musicians tend to blame everyone but themselves. I've had guitarists ***** and moan about a loud buzz, not realizing that it was their own amp...just amplified and put over the house and monitors. What you need to do in this case is a process of elimination. Turn off the mic, and listen to the guitar amp.....does the buzz stay there? If it does, then you know it's a problem with the guitar. If that doesn't fix it, try swapping out mics, and then swapping out cables. If that doesn't fix it, try using the same mic and cable on a different channel. If that doesn't fix it, check any outboard gear that you have inserted onto the problem channel. And if THAT doesn't fix it.........something's really messed up. But I'd be willing to put money on the guitar amp being the problem. Check it out yourself......musicians tend to not know how to diagnose problems. Most of the ones I see think an amp buzzing/humming loudly is normal, "cuz I got the distortion on dude".