Intermittent Buzzing

[RickyLee]

Have you verified the Grounds at your house?

Also verify your hot and neutral wires polarity is correct on your wall recepticle.

 

[Micky]

Could also be faulty wiring in the guitar.

 

[neikeel]

Sorry to have missed this in the thread but have you tried the same amp/guitar/cab set up at another house or rehearsal room?

 

[knucklebut]

I would have told him to try a good conditioner/regulator but that would be another purchase.

Besides a clue he did give is that there is no noise issue when nothing is plugged into the amplifier INPUT. That is not to say the noise source isn't the utilities.

Well ya know.....if ya cant afford the tires...dont buy the car..:minions:

 

[Micky]

OMG! I just went back and listened to the sound problem he posted.

I'm done here.

 

[RickyLee]

OMG! I just went back and listened to the sound problem he posted.

I'm done here.

I am getting ready to have a listen, but have to head out to band rehearsal.

But what did you hear? Aliens sending code messages?

 

[RickyLee]

Your sound clip reminds me of a Police scanner type of noise. I am thinking your guitar is acting like an antenna in conjunction with something going on in the amp, and maybe even some oscillations. I have no JVM experience, but I would say to check everything around that power supply circuit where the MAINS or wall voltage comes into the amp. And then check your shielding and grounds on your guitar as well as around the input branch of the amp.

As Guitar Rocker mentioned, you should check the coupling caps for DC as well. You should only have any measurable DC on the upstream side or input side of the caps. Check their respective solder pads/connections as well.

But I have experienced something similar here at my house on one phase of my 125VAC, when the laundry room appliances get used.

 

[Trophlin]

Seriously, I think it's in the electric line. I've seen it before.

Ken

I believe you Ken, than you.

I would have told him to try a good conditioner/regulator but that would be another purchase.

Besides a clue he did give is that there is no noise issue when nothing is plugged into the amplifier INPUT. That is not to say the noise source isn't the utilities.

What good conditioner/regulator do you recommend?

I double checked with no instrument cord plugged in for a much longer period of time (~10 minutes) and I heard a few noises that weren't frequent nor consistent. A couple of times sounded like the original noise but lasted for a split second (heard 2 zaps in sequence) and I heard a fizzy/hissy noise (other than the typical hiss) that lasted a split second, went away for a split second, came back for a split second, then finally went away. That was about all in that that timeframe.

Have you verified the Grounds at your house?

Also verify your hot and neutral wires polarity is correct on your wall recepticle.

I checked the outlet of where the amp is plugged in and the power and neutral are correct (small slit - hot, large slit - neutral, in the US) using a digital multimeter (tested at 122V). How would I verify the grounds?

Sorry to have missed this in the thread but have you tried the same amp/guitar/cab set up at another house or rehearsal room?

Not yet, but I will be taking it within the next few days to test it somewhere else.

OMG! I just went back and listened to the sound problem he posted.

I'm done here.

Could you please elaborate?

 

[RickyLee]

If you have a somewhat newer house and you have Grounded wall recptacles all throughout, you should be fine there. And I did see you plugged the amp into other outlets which is good.

But you would first physically check your residence to verify that you do have an actual Ground rod driven into the earth at your service panel. And then check the panel to verify the Ground buss as well as the Neutral buss.

But if you checked hot & neutral, you would check those each to Ground terminal. If you measured neutral to Ground and seen something like 50VAC, then you measured 70VAC from hot to Ground, that could be an indicator that a Ground is bad/missing, maybe right inside that wall outlet. But you first check for your 120VAC H to N, then check H to G for same reading then check N to G to make sure it is 0V.

Hopefully I explained this OK as I have to split to rehearsal.

 

[mickeydg5]

I am almost sure it is an external source. Someone is fuucking with his space.

 

[Trophlin]

I am getting ready to have a listen, but have to head out to band rehearsal.

But what did you hear? Aliens sending code messages?

I am almost source it is an external source. Someone is fuucking with his space.

HAHA It wouldn't surprise me! I do live directly across from the IRS...

 

[mickeydg5]

You are busted!

For what I have no idea.

 

[Trophlin]

If you have a somewhat newer house and you have Grounded wall recptacles all throughout, you should be fine there. And I did see you plugged the amp into other outlets which is good.

But you would first physically check your residence to verify that you do have an actual Ground rod driven into the earth at your service panel. And then check the panel to verify the Ground buss as well as the Neutral buss.

But if you checked hot & neutral, you would check those each to Ground terminal. If you measured neutral to Ground and seen something like 50VAC, then you measured 70VAC from hot to Ground, that could be an indicator that a Ground is bad/missing, maybe right inside that wall outlet. But you first check for your 120VAC H to N, then check H to G for same reading then check N to G to make sure it is 0V.

Hopefully I explained this OK as I have to split to rehearsal.

The house is 2.5 years old and it does have grounded wall receptacles.

I'll check the ground rod tomorrow. I am unsure how to check the ground and neutral buss so I'll research to see how to do that.

I did check G to H (122VAC), G to N (0VAC), and N to H (122 VAC). You did a good job explaining it, thank you.

 

[Trophlin]

You are busted!

For what I have no idea.

Well please tell them to come and get me so they can stop sending me signals!!

 

[Trophlin]

As far as shielding I have a 335 semi-hollow so I'm not too sure how much shielding will help.

 

[miallen]

Sorry, yes that is correct. So when the volume is at max the noise is at max, when the volume is off there is no noise (i.e. the weird buzzing nor the typical gain hiss).

This is an important clue.

If you turn the volume down ON THE GUITAR and the noise goes away, that means the noise is definitely not the amp. It would have to be something connected directly to the volume control. So if you think about it systematically and trace it back, it could be:

• The circuitry around the grid of the first gain section
• The input jack (such as corrosion)
• Something connected to the ground of said input circuit (like maybe the earth ground is not good)
• The cable
• The guitar jack (such as corrosion)
• The guitar circuitry (is it active?)
• The pickups

Think about it, you are basically saying that when you ground the wire connecting the pickups of your guitar to the grid of the first tube, the noise goes away. Thus the noise must originate from something connected to that wire or it's ground.

Another way to say the same thing is that this completely rules out everything after the input jack circuitry. So the amp is fine.

My best guess would be that you actually have some other device like some pedal that is using a separate power supply. And it would not have to actually be connected in series. It could be just connected to the same ground. Meaning the device is injecting noise into the ground. So make sure you check just the guitar connected directly to the amp.

Otherwise, it's probably radio interference. If you rotate the guitar horizontally and vertically does the noise change? Your neighbor just hooked up "wireless speakers" or something like that. Try it way out the back yard using an extension chord. If it goes away, it's definitely radio interference in which case you're SOL (unless you put a grounded metal screen around the entire rig including yourself).