Video for Marshall MG15dfx noise

[Stratlingun]

In reading various post I see that hum does not mean the same thing to every one, so I posted a video of my amp to youtube. If you could please bear with me, I am new to guitar playing and amps. I have a back ground in electronics( mostly been a board puller ) but never studied amps. Is this normal or what am I facing? I believe I could fix it if I new where to look.
click link below.

Marshall MG15DFX .MOV - YouTube

Thank You

[Enzo]

My computer lacks sound, so...


Hum in this game refers to power line frequency noise at either findamental or twice freq. The white noise type sound of a high gain amp channel we refer to as hiss. The sort of random burbling of a noisy resistor, well, that and other things we just call noise.

Buzz we generally reserve for a vibrational sound, like the speaker cone touching something of a loose bit on the chassis vibrating audibly.

[Stratlingun]

Thanks for your response Enzo.
I gotta say though, a computer with no sound..., it makes me cringe just to think about it. My computing and internet experience is so wrapped up in sound that with out it at least half of my computer use would be over. there would nothing left for me but reading and learnng... Duohh.

[Enzo]

You ever stop and think of adding up all the pointless You Tube links people send through the year, and all the hey-isn't-this-funny links, and all the TV show moments and reruns and other stuff that people send, and how much time it wastes? I could throw away a couple hours a day just wasting time looking at funny cats, or a dog wearing a hat and howling to some music or a "funny" political ad parody. Not only do I no longer face temptation by stuff people send me, I also no longer will throw a DVD into the computer and wind up watching a movie when I should be working.

Nothing personal, if anyone gets enjoyment from all that, then more power to them. From my perspective, instead of watching some guy in Korea or AMsterdam, or on the high seas, standing on his head while playing Stairway to Heaven backwards, I'd rather pick up my own guitar and play something.

Just me.

And I truly am an old fart, I don;t have a smart phone, I don't have apps, and I don;t have my nose in some electronic device 24/7. Well, other than the electronic devices I service for a living.

[Prairie Dawg]

You ever stop and think of adding up all the pointless You Tube links people send through the year, and all the hey-isn't-this-funny links, and all the TV show moments and reruns and other stuff that people send, and how much time it wastes? I could throw away a couple hours a day just wasting time looking at funny cats, or a dog wearing a hat and howling to some music or a "funny" political ad parody. Not only do I no longer face temptation by stuff people send me, I also no longer will throw a DVD into the computer and wind up watching a movie when I should be working.

Nothing personal, if anyone gets enjoyment from all that, then more power to them. From my perspective, instead of watching some guy in Korea or AMsterdam, or on the high seas, standing on his head while playing Stairway to Heaven backwards, I'd rather pick up my own guitar and play something.

Just me.

And I truly am an old fart, I don;t have a smart phone, I don't have apps, and I don;t have my nose in some electronic device 24/7. Well, other than the electronic devices I service for a living.

This.

[52 Bill]

OK, so I watched and listened to your video. With nothing plugged into the amp it was silent. When you plugged in a cable that was not connected to anything, it hummed and buzzed. That is completely normal and is not how the amp was designed to be used. Under no normal usage would you leave a guitar cable plugged into the amp input and not have it connected to something else on the other end.

Now if I could find a way to kick the habit of coming here to this forum and wasting time reading Enzo's posts, I could probably rule the world.

[Fragger]

Nothing plugged into my old Samick 40watt combo, clean channel, as I raised the volume, no hum, very slight hiss increased.

Plugged in guitar cord, raised volume, little hiss, moderate hum increased.

Plugged in speaker cord, raised volume, little hiss, alot of hum increased.

Is the shielding intact in the guitar cord?

[Stratlingun]

OK, so I watched and listened to your video. With nothing plugged into the amp it was silent. When you plugged in a cable that was not connected to anything, it hummed and buzzed. That is completely normal and is not how the amp was designed to be used. Under no normal usage would you leave a guitar cable plugged into the amp input and not have it connected to something else on the other end.

Now if I could find a way to kick the habit of coming here to this forum and wasting time reading Enzo's posts, I could probably rule the world.

Sounds exactly the same with guitar pluged into other end of cord. I just showed it that way to rule out the guitar. I have also tried 3 other cords alone, and pluged into 2 other guitars, sounds the same.

[Stratlingun]

Does this sound like a possible grounding problem or is something leaking? and why does the volume of the noise double and deepen when overdrive volume goes from position 6 to 7?

[Stratlingun]

You ever stop and think of adding up all the pointless You Tube links people send through the year, and all the hey-isn't-this-funny links, and all the TV show moments and reruns and other stuff that people send, and how much time it wastes? I could throw away a couple hours a day just wasting time looking at funny cats, or a dog wearing a hat and howling to some music or a "funny" political ad parody. Not only do I no longer face temptation by stuff people send me, I also no longer will throw a DVD into the computer and wind up watching a movie when I should be working.

Nothing personal, if anyone gets enjoyment from all that, then more power to them. From my perspective, instead of watching some guy in Korea or AMsterdam, or on the high seas, standing on his head while playing Stairway to Heaven backwards, I'd rather pick up my own guitar and play something.

Just me.

And I truly am an old fart, I don;t have a smart phone, I don't have apps, and I don;t have my nose in some electronic device 24/7. Well, other than the electronic devices I service for a living.

My friends know not to send me nor do I watch the type of crap to which you refer. I agree with your view on that. I just love music, a "good" movie( my laptop is plugged into my TV ), and I am taking guitar lessons online. I think its wonderful to be able to watch and listen to so many different playing techniques on the internet. I also don't have a "hip" phone, and don't text( that is unless you consider this a texting of sorts ), its much easier to talk.

[cjlectronics]

I would pull the pc board and resolder all the joints on the PCB, paying close attention to the input jack. I recently repaired an MG50DFX and a solder joint on input jack was hanging on by a thread causing low volume and crackling (is that a word?).

[52 Bill]

Plug your guitar into the amp. Now turn the guitar's volume controls to zero. How much hum is the amp making now?

[Stratlingun]

Plug your guitar into the amp. Now turn the guitar's volume controls to zero. How much hum is the amp making now?

OK you're on to something. With guitar plugged in and volume at 0, amp is quiet, just a bit of hiss. Noise increases proportionally with guitar volume. Are you saying it is normal to make that much noise plugged up to guitar with volume up when it(guitar) is not being played.

[52 Bill]

What I am trying to point out to you, is that the amp may not be the cause of the noise/hum.

You have shown yourself that the amp is increasing the volume of both the noise and the guitar signal, which is what it is designed to do. The amp can't tell the difference between music and noise, so it makes it all louder.

What sort of guitar are you using? What kind of pickups does it have? If you move the guitar around in different positions will the hum and noise change?

[Stratlingun]

This is getting really interesting now.
First 3 guitars I tried were Strat styles with single coils. So I plugged in a Les Paul style with dual humbuckers, guitar volume at 0. As I raise guitar volume, noise increases as usual..., until I get to volume level 9-10, then noise goes away..., completely ????
Is this because humbuckers are now at full noise cancelling potential? and why does noise increase up to that point insted of decreasing all the way. I rechecked the Strat, at full guitar volume I still have noise even in positions 2 and 4( suposed noise canelling ). Noise does vary slightly moving guitar around amp, or guitar and amp around the house.