Burning 845 tube.

Here's an 845 with a leak somewhere. The atmosphere has gotten inside. Watch as the filament quickly oxidizes when powered up.

Category:

Science & Technology

Tags:

• heater
• tube
• filament
• 845
• triode
• amplifier
• valve

[w1ngsfly]

Yes, that is correct.

[w1ngsfly]

It wasn't NOS. The tubes were made within the last five years I would expect. I think they are Shuguang tubes, from China. Still a shame to have a broken one, but they are fragile.

[w1ngsfly]

The tube's seal was broken during shipping. You can see the heater is burning when the tube is powered.

[3Deity]

@PSPandGPS Chinese £100, NOS General Electric VT4-C £6,000 each. I've seen one die, not a Chinese one either.

[3Deity]

@hammeredinfire I had to break a 300B once (to make a model of the guts - it was dead) and that threw the hammer up in the air and left pieces of glass in the leather glove I wore. I had my arm out of the factory door at the time, round a corner - I'm not stoopid! :o)

That said, I can honestly say I have never heard of what you claim anywhere, not hifi, studio or from being a rock guitarist for nearly 30 years. Its beyond belief that this could happen unless the glass was fractured to start with

[hammeredinfire]

WARNING: A gassy tube can explode if you turn the heater on. Filament heat will pressurize the gas inside so much that it blows up like crazy. That can be a real shock if you’re up close watching what’s going on inside when it happens.

[Nivicoman]

Someone ambitious could repump a tube and seal it at home in the case of rare ones you can't just get on ebay or whatever. It might not be complicated to use a vacuum pump and small torch to tip off the seal. I saw a lightbulb collector who did that with a rare carbon filament bulb that had the seal tubilation broken off in shipping.

[proazazel]

That was awesome! It changes my life! THX YOU!!!!

[lazzer408]

@pantyflash Like, totally groovy comment scoob

[pantyflash]

Like, awesome smoking & burning. Now we need to design a special tube that will smoke & burn this way for hours on end. Its combustible elements will be easily replaceable, so depleted tubes can be replenished for more exciting smoking & burning action. Way to go, babe!

[LectronCircuits]

Too bad it's no longer "Totally tubular, dude!" What a bummer, man.

[therealromster]

I was expecting the tube to be running hot in the purple zone, this is a loss of vacuum causing the heater to burn up like a light bulb with oxygen in it.

[rw5791]

if the seal broke in transit the flashing would have evaporated.You should have sent it back and got a refund.