Yesterday I bought a used Peavey Blazer 158 practice amp from a neighbor. I got a really good price (compared to eBay) and it seems like a good amp. The previous owner upgraded the speaker from the original to a Kendrick, and with his guitar plugged in it sounds great.

With my guitar, the high ranges sound absolutely ear piercing, and I get a real loud hum out of the thing with the volume turned up, especially with the distortion turned on. I noticed that the hum gets louder and more pronounced if I put my hand on the top of the unit, especially if I touch it under the handle.

Is the noise normal? I heard two new amps at the music store making the same noise at idle. Is it something that could be helped with a line filter for the power input, or even one of those ferrite beads for the power lead?

Thanks








_________________
Consistency is only a virtue when you’re not a complete screw-up!

Dan H
Pembroke, MA

does the noise get fainter if you move away from the amp ? ....that could just be interferance.

of if you do not touch your guitar does it still make the noise ?....i wonder if it is a ground issue ?

thats all i can think of this morning ...my brain isnt awake yet








_________________
"That is not dead which can eternal lie
.... Yet with strange aeons even death may die"


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Could be lots of things:

EMF, turn off any TV or computer monitor you are even remotely close too.
Ground, make sure the amp is plugged into an outlet that is properly grounded. In addition your guitar may not be properly grounded, check your wiring.
Cable, cheap cables can cause unwanted interference into your signal.

There are more reasons for noise, but I would check these first.








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The SHERD Shop - Where the SHERDERS shop

Without anything plugged into it, and with the amp plugged into a correctly grounded outlet, I can get it to make the sound by turning up the “pre” knob in the Lead section of the panel. Anything over 5 caused the amp to hum or buzz depending on how high I turn the knob.

It gets louder if I pass my hand over the top of the amp.








_________________
Consistency is only a virtue when you’re not a complete screw-up!

Dan H
Pembroke, MA

landy67 wrote:

Without anything plugged into it, and with the amp plugged into a correctly grounded outlet, I can get it to make the sound by turning up the “pre” knob in the Lead section of the panel. Anything over 5 caused the amp to hum or buzz depending on how high I turn the knob.

It gets louder if I pass my hand over the top of the amp.

are you a Jedi Knight by any chance ?








_________________
"That is not dead which can eternal lie
.... Yet with strange aeons even death may die"


proud member of G.A.U.P , and C.G.A.A

are you wearing a digital watch on the hand you are waving over it? What guitar was he using and what guitar are you using? It could be a difference of pickups (single coils vs. humbuckers) or shielding and wiring issues. Make sure everything on the guitar is connected, especially around the guitar's cable jack. I've had this come unsoldiered on my first guitar and it starting making terrible noises. Also, if your guitar has single coils, they are a lot brighter in sound than humbucking pickups and have a 60-cycle hum that can get really loud if you use extreme gain settings. (single coils are jut one pickup with 6 pole pieces sticking out of them, unless they are lace sensors...which were on my first guitar, humbuckers are 2 pickups fused into 1 and if the coils are exposed then they have 12 pole pieces, if it has a cover, it's rectangular and has 6 screws at the bottom of the bridge pickup and top of the neck pickup.) didn't know if you knew all of that, and I don't want my explanation to insult your intelligence or anything...

-AJH








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May the farce be with you.

Although I have not had any formal Jedi training (Dad was too lazy to do it when I was young) I am able to do the ZZ Top guitar spins without a swivel attached to my belt. I also haven’t had to learn to play the guitar to become a rock star, I just wave my hand at the audience and say with confidence “This was the best concert ever!” I always leave em wanting more…

I can make it do its unpleasant noise even without a cable plugged into it. There are two gain controls on the front one labeled PRE and the other POST. The hum (probably a 60 cycle thing) is directly related to the PRE setting. The higher it is the louder it is.

As for the guitar thing… I’m playing a Fernandes Nomad with a Humbucker pickup, and by neighbor is playing a Stratocaster with single coils.








_________________
Consistency is only a virtue when you’re not a complete screw-up!

Dan H
Pembroke, MA

amps , CAN just be noisy all by themselves ....but the hand waving is whats odd to me








_________________
"That is not dead which can eternal lie
.... Yet with strange aeons even death may die"


proud member of G.A.U.P , and C.G.A.A

Do you know if this is a tube based amp? The think has been sitting in the guys house since it was new without being plugged in. I wonder if the caps have gone flat from dis-use. As I recall from my days as a TV/Radio repairman, those things have a shorter shelf life if they don’t get used.








_________________
Consistency is only a virtue when you’re not a complete screw-up!

Dan H
Pembroke, MA

its a solid state amp....soooo no tubes to go bad or caps to dry out.








_________________
"That is not dead which can eternal lie
.... Yet with strange aeons even death may die"


proud member of G.A.U.P , and C.G.A.A

Well, the caps being refered to are in the power supply. They exist on tube amps and solid state amps. But it usually takes a long time for them to go bad. Also, just because the capacitors get drained, landy67, that doesn't mean that they won't work anymore. Those amps can sit for several months in a warehouse without ever being turned on. Either it is simply a bad design (I haven't had too many problems with Peavey, though) or there is something wrong with the circuit board or a component on it. It would probably cost more to get it fixed than what you paid for it. Although if you used to be a tv/radio repair person you might be able to figure out what's wrong with it and fix it yourself.
To answer your original question, no it's not normal.