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Loud buzz on all guitars


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Friends, I have a Marshall DSL40C (the newer one, not the 90's one) that usually does really well, but today at rehearsal, I switched over to the red channel after using an OD and the green channel for a year and my guitar (ES-333) hummed very loudly. Touching metal or strings didn't stop it, just rolling down the volume knob on the guitar. I tried switching back to the green channel, cables, and then power cables, and even plugging my guitar into my colleague's amp but it still had a buzz. I concluded that the output jack might've been wonky or grounding cable came loose... something to do with the guitar. So when I went home I plugged in the setup with same guitar but had it on the green channel. To my surprise, the green channel was very quiet. I did hear a faint hum still, but only after it was turned up loud. Switching over to the red channel, however, produce that jarring and obnoxious loud hum again. How could this be, since I plugged my guitar into my friend's amp, whose guitar was not really buzzing, and mine still buzzed?

 

I then cycled through my Les Paul and SG and both had the same results. Very slightly hum on the green channel (more noticeable if I kicked on the OD pedal, but not obnoxious), but jarringly loud on the red channel.

 

Given this information, would you conclude that this is an amp problem, particularly just that red channel, or are all my guitars un-grounded? I tried plugging in my StingRay just to see if it buzzed. It didn't buzz, but there was a very noticeable hiss. It's just a little confusing. Trying to find the source of the problem.

 

Let me know if you'd need a video or something to hear it. Thank you in advance.

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Sounds like an issue with the amplifier's red channel for sure, and not the guitars.

 

So, just to clarify, you have played thru this amp for a year, and never heard this problem before?

 

Also, are there wireless internet routers recently installed at either your home or yesterday's practice location?

I have two amplifiers that pick up a horrible noise from the at+t router here in my house, and from the similar one at Bob the drummer's house.

Most concerning it is!!

 

[crying]

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Well from what I know..

 

If your guitar is grounded properly, any buzz or hiss will reduce when you touch the strings... Then usually if its not grounded properly it will buzz more when you touch the strings...

 

If you tried several guitars out its unlikely they would all develop a ground issue at the same time.. So it kind of sounds like its something to do with the amp...

 

Or a more simple (and obvious) question.. have you tried different guitar leads??

 

Unfortunately loads of stuff can cause amps to buzz, computer equipment, strip lighting, light dimmer switches, fridge motors.. all sorts of things. Sometimes it can be hard to tell what the cause is...

 

I guess the other thing to try is just open the control cavity up, give the connections a wiggle and see if anything is loose.

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Thank you for the responses!

 

I'm starting to suspect it was a combination of the amp and the environment, as I'm at home and am on the green channel again, with no obnoxious noises (save for light hiss and hum that can be rectified by distancing myself away from the amplifier). I've had the amp for a year but have just been playing the green channel with an OD pedal, as the red channel was a little too hairy the first time I've tried it. It never was that noisy as it was yesterday at rehearsal though. I'm thinking of checking out the preamp tubes. Hopefully something's gone wrong there and a simple preamp tube swap will clean it up. It isn't so pressing, as I don't normally use the red channel, but there is still a light hum on the green channel that could be due to some bad tubes.

 

I do have another question, however. I plugged all three of my guitars into my Mainstage unit on my iMac (used for recordings and such) to see if it's indeed a ground issue with the guitar and this is what I found out:

 

Les Paul: no noise, hands off OR on strings/metal

ES: light buzz with hands off strings/metal

SG: light buzz with hands off strings/metal

 

I've always thought that was indicative of faulty wiring, but from what you're saying, that's normal? The SG has a ground wire that runs from the neck volume pot into the back of the vibrola tailpiece. I took made sure that it had contact with the metal, but it still buzzed a bit with hands off the strings/metal. Does that have to be soldered on to ground? Is that dangerous? Is it normal and safer to have a buzz when not touching strings/metal? In that case, why is my Les Paul silent?

 

I used a multimeter to check the guitars this morning (with limited to no knowledge of what I was doing). I flipped it to the continuity setting (looks like a wifi signal?) and this is what I found out with an alligator lead clipped on to the input jack socket:

 

Les Paul: No connection (or beep from the meter) on bridges or pickups, but when I touched the socket of the pickup selector switch, there was a connection.

SG: No connection from any of the pickups, but there was a connection when touched with the vibrola tailpiece (which would make sense, right?).

ES: It beeped from every metal part on the guitar, from the pickups to the bridge to the stopbar.

 

I thank you in advance for taking the time to read and then respond to this lengthy question. Will you please explain what exactly is happening with the guitars and what these meter readings mean? Which guitars have grounding issues that need to be addressed? Will there ever be a situation where this can be lethal in regards to electrocution?

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I've always thought that was indicative of faulty wiring, but from what you're saying, that's normal? The SG has a ground wire that runs from the neck volume pot into the back of the vibrola tailpiece. I took made sure that it had contact with the metal, but it still buzzed a bit with hands off the strings/metal. Does that have to be soldered on to ground? Is that dangerous? Is it normal and safer to have a buzz when not touching strings/metal? In that case, why is my Les Paul silent?

 

 

Yup its very normal.... also it depends on exactly how hard the buzz is... bad buzzing obviously is not normal but some hum is to be expected.

 

Also it will depend on what sort of pickups you have.. Single coils generally always hum.. Humbuckers not so much but you ca stil get hum...

 

And im not sure exactly why some guitars are more silent.. Were the tone and volume controls all the way up?? what pickup positions did you try.

 

Even when you have one that sounds silent.. You can still hear the effect if you just turn it up till you hear some hum.. When you touch it (at really loud volumes) theres often a small click then the hum reduces..

 

And yes the bridge ground should go on the back of one of the pots, and then there should be a ground loop so each pot wired to the other or sometimes they use a base metal plate where all the grounds are connected...

 

As for the multi meter I will leave that for someone else to answer before I make myself look silly :) but you say you connected it to the output jack.. but what part of it? On the inside you have two lugs for the ground one for live..

 

Heres a vid that may help

 

I also hear from some people that covering the backplate with shielding can help.. Check this vid

 

I also have one more question.. Do you play with a mobile phone in your pocket? Ive found that sometimes that can cause some interference.

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These guys have humbuckers. No P90's or any single-coil type pickups on them. That's why it was just a bit of a let down to hear the hum. It's not too bad, not a jarring buzz, but you can definitely hear it. In a live situation, it wouldn't be a problem because I'd have my hands on the strings at all times, but it was just something that if it needed to be fixed, then I wanted to fix it.

 

I just clipped the alligator lead on the outside socket of the input jack. Didn't open the back panel for continuity testing.

 

After watching the video of the noisy Les Paul, I remember that my Les Paul has that metal tray that was found on 70's Les Pauls. That could be why it's more silent than the ES and SG, which don't have that tray. In that case, as long as it's not potentially dangerous, I don't think I'd need to worry too much about. It's not going to affect recording or performance (since hands are on strings all the time).

 

I'd still like to know what those multimeter readings were all about though. Thank you for the responses so far. I'm feeling a little less uneasy about this situation.

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Well an idea for you...

 

If you don't get any more responses on this thread.. Start a new one in the Les Paul or the Lounge section.. they get much more people in there and you will get way more answers...

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