I go to play my guitar today, turn on the amp and this loud buzzing sound comes from the cabinet, meanwhile last night it was perfectly fine. Its a Valvestate 100R head (has one 12ax7 tube) and JCM900 cabinet. If the guitar input cord is not plugged into the amp the buzz goes away completely, but as soon as i plug in the guitar cord the buzzing gets really loud even with the volume off on the amp and it didnt make any difference if a guitar was plugged into the other end or not.

If you walk up to the amp or touch it or whatever the buzzing goes very quiet, but as soon as you move away it gets really loud. I swapped the power cord, speaker cabinet cord, guitar cords, and its still there. I even tried line-out from the amp into my computer and it was there (but not as loud). There are no fluorescent lights or anything in this room. I shut all my other equipment off (to remove any interference), i even tried a different power outlet.

So basically it sounds like its using me and the guitar cable as an antenna. Sometimes i actually pick up radio sounds through it. From what i know, it sounds like a ground problem, but where.... the input? I took the amp out of the shell for a visual inspection and found nothing. I'd take it to a shop but there are none here. The closest one is an 8 hour drive, any help is appreciated. I do have some electronics knowledge... just need a place to start looking. Does a blown tube do this? Its got a LOT of hours on it... but it doesnt really seem like a tube issue to me.

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Ground problem, as well as a possibly crappy electrical foundation. Are you using a grounded outlet? Is the wiring in your guitar properly grounded? Try it with a different guitar. It's the guitar's grounding problem if you get hum and buzz when you're not touching the metal parts on it.

If you're pretty close to your PC there's a problem too.

Replacing the preamp tube is also a very good idea, as stock tubes generally suck.

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If you touch something and the sound goes away, its a grounding problem. I would check the guitar first, and replace the preamp tube just because you should.

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Is it just like if you plugged the cable in the amp but not the guitar? Did you try cleaning the input jack on both your guitar and amp? A can of contact cleaner is like $8 and is useful for so much stuff. I had the exact same problem a week after i got my most recent preamp, 4-5 spray/dry/spray/dry sessions fixed it.

However the jack might have became a little loose, it's like when you first have sex with a virgin she's nice and tight, but as time progresses she'll get more and more sloppy and in the end it's just like thrusting into a mountain cave.

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edit: no, it does it with without anything plugged in now. Just the head and cabinet powered up by itself it makes the noise BZZZZ

No, the guitar doesnt even have to be plugged in... i even plugged in a 1 foot stubby cable i had with nothing attatched to it (just to see what happened...) and it even made that loud buzz noise. Its using the input cable as an antenna.

I found this:
http://en.allexperts.com/q/Guitar-G...picks-radio.htm
Its almost exactly what i described.

when i move closer and extend my arms, without even touching the amp, and as i walk around the room, the buzzing gets louder and softer in relation to my distance from the amp.

It started a little while ago... say a few months, but the noise wasn't that bad. I still wondered why i could hear radio stations through the cabinet. So anyways, i just moved to a new house on friday, it sounded great at this place for 2 days and today it crapped out on me.

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Man thats a weird sounding problem, for lack of anything useful to say, how about checking inside the cab for strange malevolent buzzing pixies?

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what soeru said. your not grounded well

Try using a cable that has a shield. You can buy some cable with two conductors and a shield and build one with 1/4" TS at both ends. The shield prevents any noise and radio frequencies to get added to the original signal.

Also, see if there are any power cords crossing paths with your guitar cable. Power chords create magnetic fields around them which create buzzing when they cross paths with signal carrying cables. It may not even be this because you tried the 1" cable which was a good idea. So this may not be it.

Try different channels of amp.
Change cables that plug into cab.
Try calling a friend and use his amp in the same room you play in to see what happens.
KEEP TRYING.

I've picked up radio stations before through my amp. Too bad they were not metal stations!

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sounds like the amp itself has a grounding problem. I'd replace the tube and if it still does it, it seems its time to take the bitch in for a checkup.

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does your amp have a polarization switch on the back? try the neg, and pos. settings for it

Ahh good call! If it has one, flick that bitch!

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No theres no polarity switch. Ive had the amp out of the shell and inspected (i took electrinics in college 2 courses) and didnt find anything wrong visually. Every cable has been replaced with a different one. I moved the amp into another room and same thing.

Theres a box that the "RCA" cables from the amp run into thats mounted behind the face of the amp.. do any of you guys know what this is? I cant really get a picture of it.

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did yu try using it utside your huse?
did it work then?, if no then sorry i don;t really know what to do about it

ITS THE TTEEEWWWWBBB.

replace it and come back with your conclusion. If fix is inconclusive, take it to an amp doctor. Until then i dont think theres anything else to talk about.

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will do, thanks for the input.
Ill let you know if the tube fixes it... once its shipped to me.

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I ordered GrooveTube brand 12ax7
are they any good?

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They're alright, better than whatever was stock in your amp. But I would've probably gotten a JJ ECC83.

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They only had the groove tubes and one other brand i cant remember...

so i got it in the mail, installed and its no different. Still buzzing, still picking up radio stations through the guiar cable (using it as an antenna).

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maybe you need a new cable?

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ive tried all that. the problem is in the amp itself

does anyone here know much about the circuitry of an amp? valvestate's are fairly basic.

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ok, one other thing i noticed when i was messing around last night. After installing the tube and no change happened, i started poking around in there with a pencil, seeing if moving some wires around would affect the buzz/radio noises coming through the cabinet. I noticed when i touched the jacks on the back of the amp (lineout, headphones, cabinet out, and so on...) with the tip of the pencil, the radio noise would get much louder, as if its using the pencil/me as an antenna (and keep in mind that the only thing plugged into the amp is the input cable with no guitar)

so with that info, does anyone have any idea what would cause this?

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and a voice boomed from the heavens
BAAAAD GROUNDINNNG!!!!!!!!

just a solder joint or two to fix.

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I borrowed a friends amp and that one is doing the same fuckin thing in my place... this isnt making any sense. His amp is basically brand new... so now what?

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