Tube shelf life

If left in box on shelf is there a point where the get to be too “old”?
Have a sense, as i type, this a dumb question…but what the hell…no guts no glory
Thank you

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Great question…as far as i know:

In all the years of using tubes, only 1 case of a small
signal (air seeping into the tube)…

Have purchased many nos tubes and only 1 had gassed.

Old manufactured but otherwise unused tubes nos perform as pristine new regardless of tube age…provided they passed qc tests
when they left the factory.

Best wishes


Thx davida for taking the time

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This is in no way scientific or even attempts to explain what happens with tubes over time, but I once found a bunch of many-decades-old 6L6s in a box behind a studio. They suffered years of summer heat, winter freezes, rain, etc - and yet, I’m still using a couple of them in my guitar amp :laughing:


If tubes universally spoiled with time, like milk for ex., I don’t think there would be a market for vintage tubes.


Good point
Just got my 1st amps with tubes
Learning lots


Maybe some old tubes might be sold that didn’t pass inspection but didn’t get destroyed and ended up on the market many years later.

That’s why you should never buy tubes from a seller who doesn’t have testing data.

It’s also a good idea to identify a shop locally that has a tester to ensure matched sets when needed.


The only way to match tubes would be a tube tester that can emulate the circuit that the tubes will be used in.

The point of testing is to make ensure the tubes are performing close to their original specs. Otherwise in a system that has for instance separate inputs for L&R you could be utilizing one tube that meets original spec and another that fails. Testing simply eliminates that imbalance.

It might narrow the differences, but you could still get two tubes that might match on a tube tester and put them in circuit and still have a miss match. Most tube testers don’t even have a curve tracer to match plate curves.