# Amp Hum, Increases With Master Volume



## Ben.Last (Dec 1, 2011)

As the title says, I'm getting some annoying amp hum with my new Randall V2. The hum is on all channels and I've unplugged everything already to make sure it's not my guitar or fx. It sounds a bit higher pitched than what I would associate with a 60hz hum. The hum increases with the master volume. I can't get the knob much past 8 o'clock without it getting rather noticeable. 

My next step is to lug the thing to another outlet to make sure it's not that; I am running the power through a furman power conditioner, but it's not one of the ultra swanky ones, so I'm not ruling it out. I don't want to just check it on another outlet in the same room though; so, I figured before I break my back carrying the damn thing to the other side of the house, I'd come here to see if anyone had any ideas.


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## AK DRAGON (Dec 1, 2011)

You're going to need a noise gate to battle that hum.


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## Ben.Last (Dec 1, 2011)

With how this is acting, a noise gate seems like it would just be a bandaid on a problem that could actually be addressed otherwise.


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## Razzy (Dec 1, 2011)

Can you record what it sounds like? It's hard to say whether it's "normal" hum, or something else has gone awry.


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## Ben.Last (Dec 1, 2011)

Actually, something I forgot to mention in my op, the GSP that I'm running in a 4 cable setup has a noise gate. While it's probably not the best, it has absolutely no effect on this hum.


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## Ben.Last (Dec 1, 2011)

Razzy said:


> Can you record what it sounds like? It's hard to say whether it's "normal" hum, or something else has gone awry.



I'll do that next time I get a chance.


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## mikemueller2112 (Dec 1, 2011)

I'd definitely check it on another outlet, make sure it's on a different circuit though. I'm no amp technician, so I'm not sure what could be wrong, don't know if a bad tube could be the culprit here or not. It sounds like it's pretty much isolated to the amp. Do you have another speaker cable? I'd try swapping that as well.


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## GuitaristOfHell (Dec 1, 2011)

ISP Decimator G-string.  Problem solved.


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## Ben.Last (Dec 2, 2011)

mikemueller2112 said:


> I'd definitely check it on another outlet, make sure it's on a different circuit though. I'm no amp technician, so I'm not sure what could be wrong, don't know if a bad tube could be the culprit here or not. It sounds like it's pretty much isolated to the amp. Do you have another speaker cable? I'd try swapping that as well.



Well, like I said, I tried it without anything else plugged into it but the cab and it was still making the noise. And, yeah, wanting a separate circuit is why I'll need to stick it in another room. I'm not sure if it could be a tube. The V2 is a hybrid amp; the clean channel and OD1 are both solid state, and changing channels has no bearing on the hum.



GuitaristOfHell said:


> ISP Decimator G-string.  Problem solved.



Again, I want to make sure it's not something wrong before I simply cover it up.


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## Ben.Last (Dec 2, 2011)

http://soundcloud.com/lern2swim/sounds-from-thursday-evening

There's the sound file. It doesn't really represent the volume of the hum since I recorded it with my phone. Keep in mind, from about noon on the dial on I had to start raising my voice to speak over the hum. Also, plugged it in on another circuit; no change.


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## AK DRAGON (Dec 2, 2011)

I misread the original. If it's happening on a clean setting with little gain then something might be goofy in the power amp section. Isn't there a 12ax7 in the power amp section? If it's new from a dealer take it back and have them check it out (should be free under warranty).


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## Ben.Last (Dec 2, 2011)

AK DRAGON said:


> I misread the original. If it's happening on a clean setting with little gain then something might be goofy in the power amp section. Isn't there a 12ax7 in the power amp section? If it's new from a dealer take it back and have them check it out (should be free under warranty).



The V2 is a SS power section.


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## devastone (Dec 2, 2011)

The V2 uses a 12AT7 in the power section, basically like a PI feeding the FET power section. 

Have you tried unplugging everything from the amp to see if it is still there? If so, it is the power or the amp. Next plug the guitar straight into the amp with no effects. It could digital noise, or a ground loop. I agree with AD Dragon, if it is on both channels it is after the preamp, I'm betting on something in the effects loop.


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## Ben.Last (Dec 2, 2011)

devastone said:


> The V2 uses a 12AT7 in the power section, basically like a PI feeding the FET power section.
> 
> Have you tried unplugging everything from the amp to see if it is still there? If so, it is the power or the amp. Next plug the guitar straight into the amp with no effects. It could digital noise, or a ground loop. I agree with AD Dragon, if it is on both channels it is after the preamp, I'm betting on something in the effects loop.



Again, it's still there if I unplug everything but the cab from the amp. 

That's interesting though, I didn't realize there was a tube in the power section.


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## devastone (Dec 2, 2011)

If you have unplugged everything, including the stuff in the effects loop, and the noise is still there, it's the amp or the power, and most likely the amp if it is doing it on the clean channel. Time to see a tech unless it's still under warranty. 

I had a T2 for a while, very cool amp, a little more "vintage" sounding than the V2, but I ran out of places to use big amps and cabs...


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