Never seen a power tube fail before......

[fluff191]

Does it always blow the glass housing in half? The tube is brand new and has maybe 3 hours of playing on it. I'm thinking it was just a bad tube?

 

[MusicManJP6]

That's pretty crazy! It must have been a bad tube. I bet you can get it replaced if you contact the vendor you got it from. It's kind of cool how the top of the tube turns white when oxygen enters the tube. I had an old preamp tube go out and the first thing I noticed was the top was no longer chrome, but white instead. Then I got to looking and noticed a small crack at the base of the tube. Hopefully the failed tube did not take any other parts out with it!

 

[fluff191]

Yeah I contacted the vendor. They had better replace it! I dont think it took out anything else. The fuse popped as it should have.

The shame of it is, I am going to have to send it back! I want to keep it! Looks awesome inside!

 

[Elpelotero]

wow!

 

[fluff191]

I just did a Bias mod to the amp and this is the tube I was pulling in and out while hot and probing a few times. Im sure it was just tired of living haha.

 

[domct203]

Hopefully all is good, but I would check the screen grid resistor on that socket.

I had a tube short out in my Roadster and it took a grid resistor with it.

Dom

 

[fluff191]

Good call. Not sure how to check them on the newer heads. Are they the black colored resisters that peak out from the underside of the ciruit board?

 

[fluff191]

Nevermind. They are indeed the black resisters coming off the tube sockets. And thank goodness they are ok.

 

[MusicManJP6]

Nevermind. They are indeed the black resisters coming off the tube sockets. And thank goodness they are ok.

Saved by your fuse it sounds like. Whew!

 

[stephen sawall]

Never seen one blow like that ? I have been around tubes every day of my life.

 

[PG13]

I just had the most unusual tube failure... I installed brand new JJ 12AX7's and 6L6's in my 5150 which I purchased from the Tube Depot in Tennessee. After a 30 minute warm up and testing, I shut the amp down and fired it up the next day only to get nothing. I checked all the preamp stages and one of the JJ 12AX7's cracked dead straight vertically from the glass nipple on top of the tube to where the pins are on the bottom. I was able to work it out of the slot without it shattering. The Tube Depot's customer service is excellent and without question replaced the failed tube once they received the blow tube.
After reading one of the current Mesa posts, http://forum.grailtone.com/viewtopic.php?f=16&t=6471, I'm really skeptical to continue using JJ's in my Triaxis and 2:90.