Possible Blown Tube on LSS?

[CoolRails]

All right guys, I need a bit of help diagnosing a problem I'm having with my Lone Star Special that is about a year old. I took it out yesterday to play, and I brought it back upstairs and am playing it today.

I've been playing it for about 2 hours driving it pretty hard and all of a sudden I get a strange sound coming out of the amp that starts getting louder and louder, kind of like a low pitch whistle. Then there's a slight "pop" and smoke comes up from the right side of the back panel, near the farthest right EL84. I smell burning.

I checked the tubes, and noticed the left 2 EL84's were a bit loose and not fully connected, they were "hanging" a bit. I reconnected them, noticing that the far left one was not hot. I turn the amp back on, and the 5 watt setting now doesn't work. The other channels sound weaker and get distorted if I play it for a few minutes, and I smell a bit of burning again.

Could this be a blown tube? This is my first tube amp so I'm not sure how to proceed. I don't want to turn it back on at this point, as I don't want to F it up even more.

I need help! Any suggestions?

 

[simonich]

All right guys, I need a bit of help diagnosing a problem I'm having with my Lone Star Special that is about a year old. I took it out yesterday to play, and I brought it back upstairs and am playing it today.

I've been playing it for about 2 hours driving it pretty hard and all of a sudden I get a strange sound coming out of the amp that starts getting louder and louder, kind of like a low pitch whistle. Then there's a slight "pop" and smoke comes up from the right side of the back panel, near the farthest right EL84. I smell burning.

I checked the tubes, and noticed the left 2 EL84's were a bit loose and not fully connected, they were "hanging" a bit. I reconnected them, noticing that the far left one was not hot. I turn the amp back on, and the 5 watt setting now doesn't work. The other channels sound weaker and get distorted if I play it for a few minutes, and I smell a bit of burning again.

Could this be a blown tube? This is my first tube amp so I'm not sure how to proceed. I don't want to turn it back on at this point, as I don't want to F it up even more.

I need help! Any suggestions?

If the 5W and 15W modes are not working, but the 30W mode is, it's the 5Y3 recifier tube. That is the right most tube looking from the front.

could be the outer EL84 as well. Switch out the outer pair with known good tubes and see if that helps.

 

[Platypus]

If you saw smoke and smelled burning I would not turn the amp back on without having it looked at by a tech. Sounds like you might have roasted a screen grid resistor because of the tubes. :?:

 

[Travis]

i honestly think the first thin any LSS owner should do is change the rectifier tube to something that wont fail. Then depending on your style change the speaker to whatever you fell like.

When my rectifier tube blew it did not smoke at all, i would not have known except for the fact that no sound was coming from it except for 30 watt. Semms to me that tube is guaranteed to blow. I dont care about the warranty, but my amp rips. And no problems for 2 years since i changed that tube and replaced the fuse with a cheap radio shack fuse.

 

[CoolRails]

Thanks for the advice guys. I could see if the 5 watt and the 15 watt weren't working it should clearly be the Rectifier tube, but in this case it is just the 5 watt that isn't working.

I called a local tech and he proposed his theories which were pretty much similar, I just hope whatever it is, it doesn't cost too much. :shock:

 

[Murphy Slaw]

It's one year old?

 

[CoolRails]

Yes, it is one year old.

One more thing: right before the "pop" I heard and a bit of smoke, the amp made a sound like a motorcycle accelerating, started from a low pitch up to a high one but still had a throatiness to it.

I'm bummed about going home today.... No Mesa to Play

Guess I'll have to play my Taylor.

 

[twally]

[email protected] <[email protected]>

What rectifier tube are you now using? Mine just blew-the 30 watt setting works but I like the growl from the 5 watt setting.
Thanks,
TW

 

[twally]

****,
I don't know how to do the quote thing.

From Travis
When my rectifier tube blew it did not smoke at all, i would not have known except for the fact that no sound was coming from it except for 30 watt. Semms to me that tube is guaranteed to blow. I dont care about the warranty, but my amp rips. And no problems for 2 years since i changed that tube and replaced the fuse with a cheap radio shack fuse.

So, what rectifier tube are you now using?

Thanks,

TW

 

[Travis]

****,
I don't know how to do the quote thing.

From Travis
When my rectifier tube blew it did not smoke at all, i would not have known except for the fact that no sound was coming from it except for 30 watt. Semms to me that tube is guaranteed to blow. I dont care about the warranty, but my amp rips. And no problems for 2 years since i changed that tube and replaced the fuse with a cheap radio shack fuse.

So, what rectifier tube are you now using?

Thanks,

TW

Hi, there is a quote buton on top left of each post, you click the button above the post you want to reference.

Rectifier tube: I believe it is a 1950's GE but not 100% sure, i can pull it if you really want to know. I have TAD EL84s which i really like and a few NOS preamp tubes that i had from before i bought the amp, next time i will just get some good quality new tubes instead of NOS.

I have a 5751 in V1 which i dont really like in that spot - a friend told me 5751s are 70% output of regular 12AX7 and look to put something hotter in that spot so i am going to take that out and the rest TungSol.

Can you take a pic of the cab (4x10) when you get it? I want to get a matching 2x12, the reason is because i think 4x10 is too much as far as too loud for me. Honestly the rectified 5 and 15 watt modes is what i use most on Channel 2 and only occasionally use 30 when i play on channel 1 clean.

 

[Murphy Slaw]

I've never had a rectifier tube go bad. My Prosonic is a 96', and my Blue Angel is a 2000, and they both gig a lot and very cranked. But they both use a GZ34.

I've got a NOS Mullard I've had for years whenever the first one goes, but I thought good rectifier tubes lasted for decades.

Best of luck.

Murph.

 

[Quattroste]

My Rec tube went after about 2 years. Of course I had just re-tubed the whole amp 1 week prior and was told that i wouldn't need a Rec tube as they last for ages

OP your problem is not the Rec Tube for sure.

 

[CoolRails]

So I got the amp in to a tech in my area, he took a look at it today and said the amp has significant damage due to 2 blown power tubes. He also said the other tubes looked quite used as well.

He didn't have a definitive theory, but said that he thought it looked like I played the amp really really hard. He is recommending a full re-tube, for some reason he is replacing the 5Y3 but I am paying for the 4 EL-84's. He indicated that there was some damage to the electronics as well but didn't get more specific than that.

He said that the way I play this thing, he recommended 30 watt overall instead of using 5 watt, and also that the "way I play it", probably new tubes every 8-12 months.

I drive it hard a lot in 5 watt Channel # 2 with the Master Cranked using the Output to adjust the overall volume. That was my theory as to the heavy wear, but it is still hard to swallow considering I play the amp about 10 hours a week at about 1/3 gig volume and 5 hours a week at gig volume.

Is that really too much for the beast that is the LSS? I bought it on Thanksgiving last year!