Tung-sol reissue 12AX7 failure

[devbro]

Had my first failure with one of these and it wasn't graceful. It sounded like repeatedly ripping a guitar cord out of a live amp. When I found the tube, the entire top inside above the getter was milky white. What caused this a vacuum leak?

Brutal :mad:

[Blue Strat]

What getter = Vacuum leak.

What amp and socket?

[donnyjaguar]

Sounds like thermal runaway to me. Eventually it stressed the tube and the air got in. One thing is for certain, its whipped.

[cochese]

I tried a couple back in November and found my distortion channel was getting weaker. I replaced it and the amp went back to normal. The tube didn't stop working it just wasn't working as well as it did at first. I had also put some Groove Tubes Mullard reissues in at the same time and they still sound fine. I'm trying some New Sensor Mullard 12ax7's next. We'll see.

Just my experience, hardly a scientific test.