Is there a fix yet for the MT15 noise/hum?

DreamTheaterRules

My friends call me The Cruiser
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I tried playing the amp for a bit and now the bug zapper buzz has infiltrated the clean channel. The amp is completely unusable. I have a replacement MT15 arriving tomorrow so I'll be able to tell if the problem is systemic or isolated to the one amp.
Hate to sound like a broken record, but did you check the tubes?
 

Future Barbarian

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I checked that they were all seated appropriately and they all looked to be in good condition with no abnormal glow. I don't have any extra tubes to try swapping any out. I may try that when the replacement arrives tomorrow since I'll have both, but if the replacement works fine I probably won't look into it any further.
 

Future Barbarian

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Hi @Future Barbarian !
I understand now... I see that the Master Volume also controls the level of noise, pre-amp phase.
1. Do you have the same buzz while amp is powered on and standby off?
2. Could you try plugging your guitar (no volume) to the Effects Loop's Return and check if you still have the noise?
1. The buzz goes away in standby.
2. Tried plugging in the guitar in the FX loop return and the buzz goes away. Not sure what that means. However, when I do that it starts picking up some radio station noise.

I also received my replacement MT15 today and it has the exact same problem. Tried swapping some pre-amp tubes between them to no avail. Guess they're both getting returned. This is some unacceptable QC by PRS. Extremely disappointed in this product.
 

Gustavo Posada

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1. The buzz goes away in standby.
2. Tried plugging in the guitar in the FX loop return and the buzz goes away. Not sure what that means. However, when I do that it starts picking up some radio station noise.

I also received my replacement MT15 today and it has the exact same problem. Tried swapping some pre-amp tubes between them to no avail. Guess they're both getting returned. This is some unacceptable QC by PRS. Extremely disappointed in this product.

Hi @Future Barbarian !

1. This is cool! Mine produces a very subtle buzz that passes to the speaker. Though PRS Technical Service said it's normal... I'm not very sure. But this means that other amps might behave the same.

2. The noise comes because you are injecting a signal directly into the Power Amp (no volume control) and it might pick up some weird signals because of the high volume.

> The great news here is that we have chase down the problem to the PRE-AMP (clean, lead or effects loop).
What @Van Noord mentioned about the effects loop tube is one possibility.

Make sure you do the same test with the other amp before you send them both.
It's very odd that both have the same problem in the pre-amp phase.
 

Future Barbarian

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Once I replaced the stock JJ in the effects loop preamp spot with a Sovtek, the idling noise and radio station phenomenon went away.
@Van Noord
Did you experience the same noise as demonstrated in the video?

@Gustavo Posada
It is weird that both amps have the same issue. I tried turning off every piece of electrical equipment in my house to try to eliminate anything coming in from there as a source. Using a power conditioner doesn't change anything either. My thoughts are it's filter capacitor noise which I can't do anything about.
 

bodia

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@Van Noord
Did you experience the same noise as demonstrated in the video?

@Gustavo Posada
It is weird that both amps have the same issue. I tried turning off every piece of electrical equipment in my house to try to eliminate anything coming in from there as a source. Using a power conditioner doesn't change anything either. My thoughts are it's filter capacitor noise which I can't do anything about.

I was at a buddies house a few months ago. He has a Two Rock and a couple of Bogners that exhibit the same thing. He went so far as to hire an electrician for a day to troubleshoot things in the wiring in his house. Turns out that his source of noise came from the little device the local water company installs on water lines so they can get a meter read using wi-fi. Nothing he can do about it.
 

DreamTheaterRules

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I was at a buddies house a few months ago. He has a Two Rock and a couple of Bogners that exhibit the same thing. He went so far as to hire an electrician for a day to troubleshoot things in the wiring in his house. Turns out that his source of noise came from the little device the local water company installs on water lines so they can get a meter read using wi-fi. Nothing he can do about it.

Yeah, and there is all kinds of stuff like that around these days.
 

Black Plaid

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Turns out that his source of noise came from the little device the local water company installs on water lines so they can get a meter read using wi-fi. Nothing he can do about it.

Seems like the FCC might have something to say about this. Things aren't suppose to pump out enough signal to interfere with other things.
 

Gustavo Posada

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On Thu, Apr 18, 2019 at 11:02 PM Paul Reed Smith Customer Service <[email protected]> wrote:
Hi Gus,

From the video we find the background noise to be within spec and in line with that model. The MT15 is a multigrain stage amp and putting something like that in a small style head puts everything in closer proximity and there will be background noise.

Regards,

Matt King
Paul Reed Smith Guitars
Customer Service
380 Log Canoe Circle
Stevensville, MD 21666
410-643-9970
 

Gustavo Posada

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On Mon, Apr 22, 2019 at 10:46 PM Paul Reed Smith Customer Service <[email protected]> wrote:
Hi Gus,

There can be a little bump switching out of standby however there shouldn’t be much noise while in standby position. From the video we did not hear anything that seemed out of spec.

Regards,

Matt King
Paul Reed Smith Guitars
Customer Service
380 Log Canoe Circle
Stevensville, MD 21666
410-643-9970
 

Van Noord

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@Van Noord
Did you experience the same noise as demonstrated in the video?
No, mine only had a hum when taken off standby. It was louder than a normal amp operation hum. It has since diminished.
I noticed your noise was only present on the lead channel and went away when you switched to the clean channel?
 

Gustavo Posada

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No, mine only had a hum when taken off standby. It was louder than a normal amp operation hum. It has since diminished.
I noticed your noise was only present on the lead channel and went away when you switched to the clean channel?
Hi @Van Noord ,
It is present at both channels, standby off.
When standby on, the small noise/hum/buzz is gone.
 

Van Noord

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Hi @Van Noord ,
It is present at both channels, standby off.
When standby on, the small noise/hum/buzz is gone.
Oh sorry I was listening to future barbarians video.
I don't hear anyting in your video that would cause any concern. Am I missing something or just not hearing it maybe?
 
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