Horrible Squealing/Feedback Issue

[Xrage]

Hello all. I'm hoping someone who knows more about tube amps than me can help.

I recently bought a PRS MT15 amp. I'm playing a LTD EC-1000 with a EVH 5150 III 2X12 cab.

First of all when turned on the amp hums loudly. And i mean LOUDLY.

The worse problem is that the amp squeals and feeds back non-stop on the gain channel. I've turned the watts down, i have the master volume at 2.5 (the dial facing straight left, and the gain also at 2.5. This is as quiet as i can get it with it still sounding decent. I have a 20 foot cord and am standing 20 feet away from the amp and it still squeals horribly.

I've tried plugging straight into the amp, i've stood facing away, to the side, even behind the amp to no avail. Cranking it is pretty impossible as the feedback is unbearable. i use quality cables. I've tried different outlets in different rooms and there's no electronic interference that i can see.

Should i sent it back to PRS or is there something i can try myself first?
Any help would be appreciated.

 

[László]

Hello all. I'm hoping someone who knows more about tube amps than me can help.

I recently bought a PRS MT15 amp. I'm playing a LTD EC-1000 with a EVH 5150 III 2X12 cab.

First of all when turned on the amp hums loudly. And i mean LOUDLY.

The worse problem is that the amp squeals and feeds back non-stop on the gain channel. I've turned the watts down, i have the master volume at 2.5 (the dial facing straight left, and the gain also at 2.5. This is as quiet as i can get it with it still sounding decent. I have a 20 foot cord and am standing 20 feet away from the amp and it still squeals horribly.

I've tried plugging straight into the amp, i've stood facing away, to the side, even behind the amp to no avail. Cranking it is pretty impossible as the feedback is unbearable. i use quality cables. I've tried different outlets in different rooms and there's no electronic interference that i can see.

Should i sent it back to PRS or is there something i can try myself first?
Any help would be appreciated.

If there's noise and microphonic feedback, you've probably only got a bad tube. Easy to check for, and as simple as replacing a light bulb, if that's what it is.

Every Mesa amp manual has a generic section on how to check for a bad tube, and replace them, and there's also a ton of info on their website (also you can download one of their manuals.

 

[Xrage]

Update. I'm not going to mess around with this amp since it's still under warranty. Already started the process to return it for a replacement. Here's to hoping the next one works properly.

 

[Deleted member 5962]

Hmmm….

 

[sergiodeblanc]

Hmmm….

Ehhh…

 

[dmatthews]

Just a tube as has been suggested. Your dealer can fix it if you don't want to do it.
That said carry on mate.

 

[RickP]

Yes, if you just bought it, return it. You shouldn’t need to fix a new amplifier.

When you get your new one, it’s a good idea to have a spare tube set around. Like the light bulbs in your home, amplifier power tubes do wear out over time, and even the long-lasting preamp tubes can develop issues on occasion. Also, the quick troubleshooting tests for tube amps require a known good tube for swapping out. Tubes are wonderful tone makers, and are pretty much maintenance free during their functional lifetime. As you’ve unfortunately discovered, if there is a problem with a poorly constructed tube it normally shows up in the first few minutes of use.

 

[Deleted member 5962]

I bought my Egnater Tweaker new. It had an intermittent issue and would cut out briefly, and from looking inside, all the tubes looked good. None were dim, no red plating, etc. When I sent in a customer service request, Bruce himself replied, and said "at least try re-seating the tubes. Pull them completely out, then put them back in. Then roll your known good tubes through pre and power sections, and if it's a tube, we'll send you a new one, if not, we'll send you a new amp." When I got inside the amp, I noticed that one of the power tubes was crooked and not pushed all the way in to the socket. Like one side was touching, the other was literally 1/4" up off the socket. I gently pushed it down until it was seated and didn't touch any other tube. Problem never happened again. Those tubes lasted for 2 years and were still strong when I put new ones in. It just wasn't seated properly. Possibly jarred loose during shipping, but those things are tight, so maybe just not pushed all the way in at the factory. When I let him know, he replied "a sincere thanks for that. Between shipping a new amp and you shipping that back, and then having a paid service tech take a look at that amp, you just saved me more than the profit margin on the amp sale."

He told me to save that email in case I ever had an issue, then he'd have record that I had one right when I first bought it, if it did ever turn out to be something else. But I kept that amp for 4 years and the guy I sold it to still uses it. No other issues.

So I guess my question is, do we as tube amp buyers have ANY obligation at all to at least do a basic check on these things prior to returning them? Or has Amazon completely taken over the world and now "there way" applies to everything?

 

[RickP]

I bought my Egnater Tweaker new. It had an intermittent issue and would cut out briefly, and from looking inside, all the tubes looked good. None were dim, no red plating, etc. When I sent in a customer service request, Bruce himself replied, and said "at least try re-seating the tubes. Pull them completely out, then put them back in. Then roll your known good tubes through pre and power sections, and if it's a tube, we'll send you a new one, if not, we'll send you a new amp." When I got inside the amp, I noticed that one of the power tubes was crooked and not pushed all the way in to the socket. Like one side was touching, the other was literally 1/4" up off the socket. I gently pushed it down until it was seated and didn't touch any other tube. Problem never happened again. Those tubes lasted for 2 years and were still strong when I put new ones in. It just wasn't seated properly. Possibly jarred loose during shipping, but those things are tight, so maybe just not pushed all the way in at the factory. When I let him know, he replied "a sincere thanks for that. Between shipping a new amp and you shipping that back, and then having a paid service tech take a look at that amp, you just saved me more than the profit margin on the amp sale."

He told me to save that email in case I ever had an issue, then he'd have record that I had one right when I first bought it, if it did ever turn out to be something else. But I kept that amp for 4 years and the guy I sold it to still uses it. No other issues.

So I guess my question is, do we as tube amp buyers have ANY obligation at all to at least do a basic check on these things prior to returning them? Or has Amazon completely taken over the world and now "there way" applies to everything?

I get you, and agree. But I also get that not everyone is comfortable sticking their hands into electronics, so if the amp arrives from a dealer and they don’t take the time Bruce did to find out if you were comfortable with checking, and provide a little direction, it isn’t on the buyer. While I accept that buying something that requires shipping means loose parts are possible, I also expect of manufacturers or dealers who offer to ship also know that it comes with the same negative possibilities the buyer fears. It has to get to the buyer functioning.

I was buying online back in the Music Emporium days, when you had to send payment through the mail, and then shipment waited until payment cleared. Sometimes it was a month turnaround. My first Boogie took 6 months! I’m not an instant gratification guy. But I also recall returning a very expensive oak Carvin X100 amp that rattled and buzzed when I got it. They also pointed to “shipping damage” though there wasn’t a mark on the amp or box damage. I told them I can’t tell that to the studio engineer, it either works right or it doesn’t. They provided no help, and got the amp back. Boogie was always stupendously supportive and kept my business until big G took over.

Lots of words. I’m only saying responsibility for a new amp working does not rest with the buyer. If you’re willing (as you and I both are) to search, test, and fix then that’s great for the amp maker. You truly did save them a chunk of change. I did the same not too far back with a person on this very forum. But if I didn't want to, was unfamiliar with the circuits, or was otherwise unwilling to do so I believe the onus is on the seller who promised a working amp to make it so. Just my opinion

 

[Deleted member 5962]

I get you, and agree. But I also get that not everyone is comfortable sticking their hands into electronics, so if the amp arrives from a dealer and they don’t take the time Bruce did to find out if you were comfortable with checking, and provide a little direction, it isn’t on the buyer. While I accept that buying something that requires shipping means loose parts are possible, I also expect of manufacturers or dealers who offer to ship also know that it comes with the same negative possibilities the buyer fears. It has to get to the buyer functioning.

I was buying online back in the Music Emporium days, when you had to send payment through the mail, and then shipment waited until payment cleared. Sometimes it was a month turnaround. My first Boogie took 6 months! I’m not an instant gratification guy. But I also recall returning a very expensive oak Carvin X100 amp that rattled and buzzed when I got it. They also pointed to “shipping damage” though there wasn’t a mark on the amp or box damage. I told them I can’t tell that to the studio engineer, it either works right or it doesn’t. They provided no help, and got the amp back. Boogie was always stupendously supportive and kept my business until big G took over.

Lots of words. I’m only saying responsibility for a new amp working does not rest with the buyer. If you’re willing (as you and I both are) to search, test, and fix then that’s great for the amp maker. You truly did save them a chunk of change. I did the same not too far back with a person on this very forum. But if I didn't want to, was unfamiliar with the circuits, or was otherwise unwilling to do so I believe the onus is on the seller who promised a working amp to make it so. Just my opinion

No, you're totally right on everything you said. And I'm not slamming the OP at all. That amp might have had a legit problem. But it was just an unseated tube (like mine) or even a bad one... sending an amp back is a lot of hassle for a bad tube. And while Les directed him to a tutorial on how to check tubes, I don't know if we even got enough info to know if he bought it from a dealer or through the mail. I don't think his post even verifies if it was new or used.

There was a similar story at TGP the other day and the guy bought new online, had an issue and said he didn't now how to "check tubes" and didn't think he should have too, so he was not only sending it back, but going to by another brand... I won't even tell you what some of the replies he got were. LOL

But to your last point, if it were SS even you and I probably wouldn't open it up and start tracing the circuit. Or a modeler! I guess I've just always thought that with tube amps there was sort of a minimum effort that might be required to make at least the simplest checks (tubes and fuses) before returning it. But that's just IMO. And, I'm imposing my thoughts from years of playing guitar as well... with admittedly a different set of rules. Most things, if I buy it and out of the box it doesn't work, it's going back. Guess I just have a different mindset about tube amps.

 

[László]

Guess I just have a different mindset about tube amps.

I suspect that our mindsets are, as usual, very similar.

 

[RickP]

No, you're totally right on everything you said. And I'm not slamming the OP at all. That amp might have had a legit problem. But it was just an unseated tube (like mine) or even a bad one... sending an amp back is a lot of hassle for a bad tube. And while Les directed him to a tutorial on how to check tubes, I don't know if we even got enough info to know if he bought it from a dealer or through the mail. I don't think his post even verifies if it was new or used.

There was a similar story at TGP the other day and the guy bought new online, had an issue and said he didn't now how to "check tubes" and didn't think he should have too, so he was not only sending it back, but going to by another brand... I won't even tell you what some of the replies he got were. LOL

But to your last point, if it were SS even you and I probably wouldn't open it up and start tracing the circuit. Or a modeler! I guess I've just always thought that with tube amps there was sort of a minimum effort that might be required to make at least the simplest checks (tubes and fuses) before returning it. But that's just IMO. And, I'm imposing my thoughts from years of playing guitar as well... with admittedly a different set of rules. Most things, if I buy it and out of the box it doesn't work, it's going back. Guess I just have a different mindset about tube amps.

I suspect that our mindsets are, as usual, very similar.

Totally not in disagreement. Even for the buyer, it’s easier to check the simple stuff. I also forget (often) that many players now have never seen a tube in anything but a guitar amp!

I’m onboard with your thought train. My own train came from the same station. Lol

 

[Xrage]

Thanks for all the good advise. Like i said, i just bought it and it came out of the box with these issues so the store i bought it from is sending me a different amp and i quess they will be dealing with the warranty for the broken one.

 

[Deleted member 5962]

Totally not in disagreement. Even for the buyer, it’s easier to check the simple stuff. I also forget (often) that many players now have never seen a tube in anything but a guitar amp!

I’m onboard with your thought train. My own train came from the same station. Lol

And I’m sure that’s part of it too. Tubes were in EVERYTHING when I was a little kid, and many stores had tubes for sale. There was a TV repairman up town that had SHELVES full of tubes and speakers (alnico magnet ones!). One of my friends dad repaired radio’s on the side as a hobby. He had TONS of tubes and test equipment. You didn’t throw stuff out when it stopped working, YOU FIXED IT. Funny memory that my brother reminded me of at church the other night. He was asking about a particular amp someone was using and if it was tube or solid state. And then he said “remember when dad was upset because we got a repair bill for $25 for one of the TVs, and it was the old one and something blew and had to be replaced, but whatever blew took out like 5 tubes. And dad was upset that he had to spend $25 to get it repaired.” I remembered that well because dad debated repair vs. replace…. Whatever blew had to be replaced and we both remembered the detail and bill, saying that 5 tubes had to be replaced… labor included, $25.

Anyway… to what you said, young people now are haven’t seen a tube before. Probably don’t even know the most basic checking of tubes. That’s where us old guys come in. We need to take these guys under our wing and say “don’t you dare send that amp back without checking the tubes. First visually, then we’ll walk you through replacing them which is no more difficult than changing a light bulb.”

And then if they say “tubes are too much hassle. I’m returning this and getting a Line 6 modeler instead” we ban them from the forum and sign them up a 20 year subscription to Vogue and free trails of …. Well, you know.

 

[László]

And I’m sure that’s part of it too. Tubes were in EVERYTHING when I was a little kid, and many stores had tubes for sale. There was a TV repairman up town that had SHELVES full of tubes and speakers (alnico magnet ones!). One of my friends dad repaired radio’s on the side as a hobby. He had TONS of tubes and test equipment. You didn’t throw stuff out when it stopped working, YOU FIXED IT.

Growing up in Detroit, every hardware store and most drugstores had a tube department with a tube tester that was as big as a washing machine, and shelves loaded with RCA, GE, and other American-made tubes.

And, yes, when things broke, they got fixed. We didn't live in a throwaway culture.

 

[alantig]

Yes, we got things fixed when we were younger. But things were made to be fixed then. Today, products are designed to be replaced instead of being fixed. And those that can be fixed are meant to be fixed by the manufacturer, not the guy down the street.

 

[sergiodeblanc]

And I’m sure that’s part of it too. Tubes were in EVERYTHING when I was a little kid, and many stores had tubes for sale. There was a TV repairman up town that had SHELVES full of tubes and speakers (alnico magnet ones!). One of my friends dad repaired radio’s on the side as a hobby. He had TONS of tubes and test equipment. You didn’t throw stuff out when it stopped working, YOU FIXED IT. Funny memory that my brother reminded me of at church the other night. He was asking about a particular amp someone was using and if it was tube or solid state. And then he said “remember when dad was upset because we got a repair bill for $25 for one of the TVs, and it was the old one and something blew and had to be replaced, but whatever blew took out like 5 tubes. And dad was upset that he had to spend $25 to get it repaired.” I remembered that well because dad debated repair vs. replace…. Whatever blew had to be replaced and we both remembered the detail and bill, saying that 5 tubes had to be replaced… labor included, $25.

Anyway… to what you said, young people now are haven’t seen a tube before. Probably don’t even know the most basic checking of tubes. That’s where us old guys come in. We need to take these guys under our wing and say “don’t you dare send that amp back without checking the tubes. First visually, then we’ll walk you through replacing them which is no more difficult than changing a light bulb.”

And then if they say “tubes are too much hassle. I’m returning this and getting a Line 6 modeler instead” we ban them from the forum and sign them up a 20 year subscription to Vogue and free trails of …. Well, you know.

That’d be like, $1700 if you’re talking about the print version of Vogue.

 

[Deleted member 5962]

That’d be like, $1700 if you’re talking about the print version of Vogue.

“Seventeen?”