Buzzing amp...grounding issue?

[Crimsontider]

Hello all.

I have a small Peavey amp that starting making the unpleasant buzzing sound a month ago. It stops when I touch my guitar, the end of the chord if not plugged into the guitar, or if I touch something metal near the speaker.

Troubleshooting. I eliminated the guitar and chord by plugging the chord with guitar into another amp w/no problem.

Any easy answers to correct the problem other than keeping my fingers on the strings?

I usually use the amp as a preamp going to a virtual amp on my computer. Everything on the peavey is set to zero except distortion and volume on 1, so the problem is minimal in this fashion, but I would sure like to fix it.

It seems like me touching it is the only remedy.

Any help appreciated

[RichRS6]

Not sure if you're in the U.K. or not but here we have Three pin plugs and I have had the Earth connection in the plug work loose and create a similar problem, and/or the mains cord breaking down internally.

Is the amp a valve amp ? If so could it be a faulty valve ?

[Crimsontider]

Not sure if you're in the U.K. or not but here we have Three pin plugs and I have had the Earth connection in the plug work loose and create a similar problem, and/or the mains cord breaking down internally.

Is the amp a valve amp ? If so could it be a faulty valve ?

From what I have done below, it must be in the amp. How to you ground an amp?

I live in the US. It's a Peavey Blazer transtube amp, whatever that means, I am assuming virtual tube but made like all other small peavey amps. I just noticed that it does not have the third ground prong. This must be an older amp with the old 2 prong. It is 40 watts I believe.

I have it plugged into a 3 to 1 adapter that is 3 prong. I am plugging the amps 2 prong chord into one of the three, 3 prong outlets. I don't have anything plugged into the others. I unplugged everything else to make sure that that was not the culprit. Also plugged it into the outlet without the adapter.

Thanks,

Greg

[crunchee]

Has the power cord been replaced? Or perhaps the '3rd' prong (ground) been removed? Is your power cord the type where it plugs into a socket in the back in the amp, rather than being hardwired to the circuit? I've seen amps where the ground was removed from the plug, as the outlets the owner used were very old and didn't accept grounded plugs. Peavey 'Transtube' amps have been around for awhile (I dunno, about 20, but at least 10 years). How old is your amp? If it was me, I'd shoot off an email to Peavey, let them know exactly what you've got (name/model of amp, model number, even serial number), and ask them. Practically ANY amp that was built for use in the US for AT LEAST the last 30 years should have a grounded plug!

[Crimsontider]

Practically ANY amp that was built for use in the US for AT LEAST the last 30 years should have a grounded plug!

Those are good ideas thanks. Looks like the original chord, the prong was never there and it connects exactly like the picture at the bottom. Mine is even older than the pic, mine says peavey at the top like the originals 80's models. But this one is the same besides that, there are much newer one's with the same name that are more modern looking.

The amp was a gift from my son in trade for 4 years tuition/books room and board at the Univ of Alabama . I believe it used to be a friend of his. I can't I have a two prong amp!!. It Kind of giggles a little, not really tight connection. I will check the connection out.

The noise can get on your nerves because I keep thinking it's something easily fixable.

Here is pics from the web. Like mentioned, mine is identical minus the location of the Peavey name. I will email them like you suggested thanks again.

Greg

[crunchee]

If the amp power plug is indeed a two prong ungrounded plug, you could always turn the plug over and plug it in again, to see if that makes a difference, Back when two prong outlets and plugs were common, and if a amp didn't have a polarity switch, that was one way to try to cure any unwanted hum. If that doesn't do the trick, then it might need to be checked out by a tech. You can still ask Peavey, though...it might be a common problem.

Also, have you tried it out in different outlets, and different locations in the house? Have you plugged the amp into a grounded surge protected strip, by chance? If it makes noise in one location, then you want to rule out the outlet itself, all other things being equal.

I can't believe that UL would let Peavey release a instrument amplifier without a ground on the plug, not over the last 30 years! But who knows?

[stobro]

I worked at Peavey in the mid-80's and every piece of equipment that plugged into a wall outlet had a 3-prong grounded plug- even the amps built into the T-15/T-30/Patriot guitar cases. I'm willing to bet that the power cord on that amp isn't the one that it left the factory with. If it has a metal chassis, the chassis has to be grounded.

[crunchee]

I worked at Peavey in the mid-80's and every piece of equipment that plugged into a wall outlet had a 3-prong grounded plug- even the amps built into the T-15/T-30/Patriot guitar cases. I'm willing to bet that the power cord on that amp isn't the one that it left the factory with. If it has a metal chassis, the chassis has to be grounded.

Stobro for the win! Sounds definitive to me.

[Crimsontider]

I think you guys have it figured out. I did notice that the noise is sync exclusively with the gain control. The clean channel is perfect and the distortion channel is fine with the gain turned off and just the post turned up.

I also suspect that the metal chassis at the top in the amp is not grounded. I have to push the guitar chord upward where it plugs into the amp sometimes because the gain peters out, but it corrects the problem for a while. I just use my thumb and apply a little upward pressure and the gain kicks back in

I am getting the feeling that I just need to purchase another practice amp. I have always liked little Peavey amps when on a budget when I was starting out and I can probably find one or a fender at the pawn shop or music store consignment shop. My amp is probably 20 years old and like mentioned, had a new chord installed along the way. No telling the how much it's been banged around. Like all Peavey's it is well constructed.

[RichRS6]

Try replacing the input jack socket.

If you have to wiggle it about to get a good connection then there's a chance that either the connections inside the socket are duff or the solder joints where the socket connects to the Printed circuit board (I'm assuming the socket is mounted directly to the PCB here as they are on many smaller amps) )have become loose due to all the plugging and un-plugging.

If it was mine I'd take the thing apart (make sure it's unplugged first) and have a look before sending it anywhere as 10 Minutes with a soldering iron could fix it.

Usual disclaimers apply here if you blow yourass/the amp to pieces etc etc.

[Crimsontider]

Try replacing the input jack socket.

If you have to wiggle it about to get a good connection then there's a chance that either the connections inside the socket are duff or the solder joints where the socket connects to the Printed circuit board (I'm assuming the socket is mounted directly to the PCB here as they are on many smaller amps) )have become loose due to all the plugging and un-plugging.

If it was mine I'd take the thing apart (make sure it's unplugged first) and have a look before sending it anywhere as 10 Minutes with a soldering iron could fix it.

Usual disclaimers apply here if you blow yourass/the amp to pieces etc etc.

I own a computer business and dealing with other people's property I pay special attention to making sure all power sources off or unplugged before getting inside. You can fry a motherboard just having static electricity in you, so you have to touch metal before any hardware repairs. It's mainly software and networking these days though.

Thanks, I will try this. I am not going to invest in any repair shop, as it's probably worth $50 maybe. If I ruin it, then I'll just buy another decent practice amp. Thanks.

I'll post if when the operation is over.

I always mocked Peavey back in the 80's because they seemed to be the amp for the beginners (like myself) or rednecks, when the hot shots were using Marshall, Ampeg's, Mesa Boogies and such. Then one day in the 90's I saw my favorite band was using all Peavey equipment and it sounded great. My first amp of any quality was an 80's bandit. My friend had a fender about the same size, and I thought it had a better high end sound, but it probably cost more and Peavey was a fairly new company. One thing you can never say about a Peavey is that is is not a well constructed amp. They are made like tanks. I feel comfortable playing through them because I always know what to excpect and should have had more respect for them back in my teens.

Greg

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