Interesting tube failure

Jondog · Post by **Jondog** » Tue May 30, 2017 12:34 pm

Was playing my TT yesterday for awhile, no issues, then took a break. Came back few hours later and nothing when I turned the amp on. Double checked my cables/fuses, all good. Pulled the shield off the phase inverter and the tube was sitting there loose in the socket because the bottom had broke off! Luckily I was able to get the bottom out without getting any pins stuck in the socket. Installed a new tube, all is good.

pedecamp · Post by **pedecamp** » Tue May 30, 2017 1:12 pm

Wow that's pretty thick glass to just explode on its own like that, never seen that before. I've only experienced one 12AX7 go bad on me in 10 years, it turned white inside and stopped working but nothing like that!

Post by **bclaire** » Tue May 30, 2017 2:24 pm

Wow... I had an output tube go on me in my AD200B once that burned a small hole right through the side of the tube and through the tube retainer!

Les Paul Lover · Post by **Les Paul Lover** » Tue May 30, 2017 7:27 pm

Impressive Jondog!!!

a.hun · Post by **a.hun** » Mon Jun 05, 2017 9:10 am

Yep, I'd say that both those valves are dead!

Jondog's is a bit unusual, but maybe the bottle was a bit weak / flawed and just went through one too many heat cycle.

Billy's looks as if it was melted by running far too hot. I'd guess the one valve was off spec and ran way hotter than the others with the set bias. That or it developed a fault with the same result.

Valves die.

Andy.

Interesting tube failure

Interesting tube failure

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