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Noise thru amp when guitar volume all the way down


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This is really weird.


I have the HD500x going into the front of my Mesa Boogie, it seems to get a better sound thru my clean channel than going thru the effects loop.


But when I turn my volume ALL the way down on my guitar, there is a very loud noise thru the amp, like a hum+white noise.

If i turn the volume knob just a hair up, it goes away.  It's only when it's fully all the way down.


I  don't have this problem when I use the Boogie by itself.

I don't have this problem when i use the HD500x by itself (with headphones)

Both of those are totally silent when i lower my volume knob all the way.


I hesitate to take my guitar into a shop, because the volume knob seems to be doing it's job fine when not hooked up to the HD500x AND and amp.

So the problem *seems* to be that combination?

I'm using Treadplate, high gain, noisegate, screamer, which is a heavy distorted tone, but why does the volume knob ALL the way down make so much noise thru it?  



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That is most curious. Usually this can mean the preamp in the Boogie might not be biased right or something is going one there. Usually, putting an active buffer between your guitar and amp will solve this. But you have the problem with the active buffer in line....This can be indicative of a cable problem some place where you have ground leakage in to places that loop back...Does it do it with other guitars also? Try different cables and different guitars if you can...

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I agree. Try flipping the phase on the HD but likely a cable.

Definitely try another guitar if possible as suggested.

Try moving the HD in relation with the amp with the volume down and see if there is

interference being picked up after the guitar.

Really check if the amp is silent with volume down when only it is plugged into the amp.

Check the mains power in the area and if near any interference.

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It's more of a really loud white-noise than hum.

I have EMG active pickups, but as I said, when going right into the Boogie, guitar volume all way down = zero noise.

So I don't see how it cold be the cable, but i'll try a few different ones to verify.

I did try another guitar (a Warlock) with non-active pickups, and the problem was the similar, but not quite as loud. 

I attribute that to the overall lower volume of non-active pickups?

Here's the weird thing, when I'd touch the plastic part of the Warlocks's volume knob, the noise would go away.

Which leads me to think of grounding on the guitars is a problem... but... grounding on 2 different guitars that otherwise silence perfectly when volume knob at zero?

Kinda unlikely.

Tried turning off lights in the jam room, no difference.

I think the whole room is on the same circuit, but I'll try plugging both into the same outlet to test.

It's really annoyingly loud at the end of songs, or breaks where I volume knob down quickly.

Hopefully there is a fix.

Thanks for suggestions, keep 'em coming please.... i'll keep ya posted.


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with the guitar vol down try moving the HD around in relation to the amp, after all it is basically a computer.

See if the noise changes.

But white noise volume down, another thing could be to try a noise gate at the end of your chain.

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Bjnette:  I have a noise gate at the beginning, no extra slots for one at the end.  Yes, I've moved it around a bit


spaceatl:  Yes, I have the pad on as it does boost my clean channel, which does sizzle if I hit the strings too hard with the pad on or off, but no noise difference.


pfsmith0:  On my guitar touching stings or  knob or jack does nothing.  On my buddy's Warlock touching the knob makes it quiet, stings not so much.  You're thinking his bridge isn't grounded right?  But both guitars otherwise are quiet through both our amps when volume knobs are down.


This is weird.  Will keep ya'll posted.

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There is much in the forum over the years on selecting Aux or variax as second input to solve a common noise problem when set to same.

Without going too deep, Your guitar is plugged in to just one input, not two.

If you select the same you do get a 6db increase in volume but it hits the FX and Amp too hard causing internal clipping and raises the noise floor to unusable.

While selecting one only for guitar input and other for variax you will have to readjust your gain staging a bit but the tonality will be better. Just turn up the Master output or monitors to make up for gain loss.

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On most patches I make sure I'm not doubling the inputs, but occasionally it can be used to good effect. With my Strat for instance, which does not have especially hot pickups, setting input 2 to "same" can be the difference between a crystal clean tone, and an SRV-ish "not quite clean, not quite dirty" tone that works nicely. Never really noticed it making the patch any noisier than those without the hotter signal hitting the amp model.

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RE: 2nd input.


Yes, I read a lot about using "same" for input 2.

While I do hear a very slight noise addition (or volume addition) it not at all unusable.

As for the clipping, I'm noticing my clean amp clips no matter what I use, still trying to figure that out.


But as I said, with my path having a clean Preamp on A, and a high gain Preamp on B, I need to set the input to Same.

Otherwise, one of the amps doesn't get the guitar sound... it seems like it passes a dry signal with the effects to the output, but bypasses the amp.


What would the noisegate have to do with anything?  I'll try it, i'll give anything a shot. 

But the problem seems to be some sort of grounding loop/white noise.  It's a constant noise, it doesn't disappear when the noisegate engages, it's always there unless I turn my volume knob up ever so slightly.

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Well, my thinking is your noise changes with input level (raise guitar level, noise drops). The gain of the noise gate also changes with input level. Compressors do too. I was just trying to think of things that could change gain based on input level.

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What about the input Z Setting? I normally set mine to 1M, I remember I was hearing some strange noise once... and I accidentally had changed it to 3.5M. This setting is more associated to "taste" or true modelling (taking the impedance of the first pedal if set to AUTO) but you should consider it also. 

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I do understand that despite advices there is still an issue and it concerns you to find the cause and therefore a solution.


The noisegate at the end of the chain was only to determine where in the chain the problem lay.


As you are close at hand your observations have the most merit and the possibility of a grounding issue is valid.


I was most upset about the amount of noise the HD made when I first got it, it was almost a deal breaker. It being a computer 


Most of my guitars have been shielded and this has illuminated the problem in them. 

I do have a passive jazz bass that is not shielded yet and it too is sensitive to slight volume changes in the different pickups. My guess it it is when the neck and bridge is engaged they are wired  like a humbucker.


Good luck with yours 

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OK, spaceatl gets the gold star for thinking it was likely a cable way back in the beginning of the thread, I finally got a chance to try the rig out at practice using a monster cable we had laying around.... and <poof!>  noise gone.


SOOOOOOO weird cuz my old cable otherwise works fine going direct in to my amp, or direct into the pod & headphones... but add the Pad and amp together and it's noise-city!.


OK, good to know.  Thanks for the suggestion.

I can't complain about my cable tho, it was a Spectraflex 20ft cable I got as a gift back in 1991 and has been thru years of gigging across Europe.

It had a lifetime warranty tho!




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