#1
So I was jamming with my bandmates yesterday, and right when we were getting in the groove, I think we heard a pop, and my co-guitarist's amp cut out. No sound.

Smoke from the amp.

Kinda worried, since earlier, about 2 hours earlier, he had forgotten to plug the speaker cable in. But no immediate bad effects from that. SO I don't think it's the transformers.

He has a Carvin V3, and there are 5 preamp tubes. 3 of the tubes seem like the silver cap on top got slightly blackened, and the innards are slightly discolored, and there are black rings on the bottom of the tubes. So I'd wager that those 3 are bad, right?

Any way to tell for sure? Could someone post a picture of a bad 12AX7?

It is possible the fuse blew, too?

I've never had a preamp tube break on me, so excuse the n00bness.
#2
Hey John.

Don't think I'm the best guy to give you advice on this but here we go:

From what I know, the 3 preamp tubes sound almost certainly dead. And usually when tubes go out violently, they take other components/tubes/fuses with them. The smoke makes me think something like a fuse or cap blew up on you too. AFAIK the only way to know for sure is to replace the tubes. But who knows maybe someone more knowlegable will come along and have something different to say.
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#4






All my tubes instead of going black have turned white on the silver cap. The first tube blew, literally broke in half, glass and all.
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#5
Yeah, why just replace 3 out of 5? I mean what's the extra $30 or so when there's a good chance the other two are on their last legs as well? Oh well.

And yeah, preamp tubes seem to rarely go violently; it seems to be an uncommon kind of thing to just have 3 blow on you at once lol that kind of sucks for your friend. But idk life's freaky like that sometimes. And it's nothing a few bucks won't fix.
Please, call me Chase.

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You live up to your name, sir. Well done.


Gear

Lefty MIM Strat
Traynor YCS50 :
Larrivee D-03R
Dunlop 95Q Wah
BYOC Fuzz
Fulltone OCD
Vintage Volume Pedal

I witnessed Night of the Pear 2
#7
Quote by forsaknazrael
Huh. Well, the 3 preamp tubes that look funny definitely don't have a white top. Is that what they always look like?


I coudln't tell you that's a guaranteed sign of a blown preamp tube, I'm sure other brands might do something different, but JJ's and Mesa tubes obviously turn white when they're broken.
Major of 7 String Legion 7 > 6

Carvin DC747
Ibanez RG2228
Schecter Avenger Custom Shop
and my baby....
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#9
Quote by forsaknazrael
^Hm, alright. Hopefully someone else might have a pic of another busted preamp tube. Maybe Sovtek..


If I'm not mistaken Mesa tubes are rebraded Sovteks and other random chinese tubes. I have horrible luck with tubes, i've probably experienced 5 preamp tubes blown, and 3 powertubes. I've only had tube amps for about 2 years!
Major of 7 String Legion 7 > 6

Carvin DC747
Ibanez RG2228
Schecter Avenger Custom Shop
and my baby....
Gibson Explorer Studio
#11
It certainly sounds like the tubes went out, but i can't say that for sure. It's really simple to pull the fuse out and check it, though, just to see if that's one of your problems.
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#13
Well here we go. I am the "co-guitarist", and its just my luck that my computer blows up and i lose everything on my hard drive; music, pictures, applications, recorded stuff, etc. AND my god damn amp decides to take a break. Well, here are the pictures of the insides as well as all of the tubes. Every pic will have its own explanation.

EDIT: There are NO fuses, only a circuit breaker.


The whole thing when i opened it.

This is between the 3rd and 4th tubes. I cant figure out what blew, it looks like a resistor.

This is between the problem area.

Just an overview of the other side; nothing seems damaged.

From a distance, both of the burnt areas.
Last edited by dogismycopilot at Feb 3, 2008,
#14

Black stuff on the bottom of the panel. (this is not good ppl)

Resistors near the 5th preamp tube

Little blackening on the 3rd main tube ceramic holder thingy.

All 5 preamp tubes. The 3 on the right have a more pronounced blackened bell on the top
#15

The 3 on the right (the ones mentioned above) have a more noticeable black ring

4 main tubes

...guess i cant play 99 red balloons anymore...
#19
if the amp doesn't smell like ****, then it's not a cap that blew up...


schematic/layout anywhere?


or just go to carvin.
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#21
Damn, and I was thinking of buying one of these, I hope this is not a comon prob.
#22
Quote by jake911
Damn, and I was thinking of buying one of these, I hope this is not a comon prob.

A tube blew violently and i have reason to believe that when i bought it, one maybe two of the preamp tubes were bad. It cost me $250 to replace EVERYTHING on it. Knobs, circuitry, panel, inputs, circuit breaker and tubes. They basically gave me a new V3 for $250.

It is a great amp, $#!T happens though.
#23
Could've been worse. You could've had to get a whole new amp for full price. I'd consider myself somewhat lucky
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#25
Quote by dogismycopilot
A tube blew violently and i have reason to believe that when i bought it, one maybe two of the preamp tubes were bad. It cost me $250 to replace EVERYTHING on it. Knobs, circuitry, panel, inputs, circuit breaker and tubes. They basically gave me a new V3 for $250.

It is a great amp, $#!T happens though.


Thats still $250 more than you should be paying...
Major of 7 String Legion 7 > 6

Carvin DC747
Ibanez RG2228
Schecter Avenger Custom Shop
and my baby....
Gibson Explorer Studio