Tube life.

[Delidroid]

Hello.
My question I’m sure has been asked 1000 times. I have tried looking without success.
My question is how long on average do Tubes last.

I have built a Champ 5F1 kit. If i turn it on every day and play for 1 hour, how long would the tubes last?
Do I ask Santa or my Grandchildren to get me some new ones please?

[R.G.]

Reasonable question, but with no clear answer. For tubes in gear other than guitar amps, they can last a very long time. But the operating conditions matter, and it was common in the Golden Age to run the tubes up to and in some cases beyond what conservative practice would allow. Amps that are used a lot might need tubes every year. But there are many counter examples. I had a Thomas Organ Vox Berkeley with the original Vox rebranded preamp tubes in it. That thing was built and sold in the early 1960s. Running tubes at high currents, a many guitar amps do, wears them out fast by exhausting the emitting oxide coatings on the cathode quickly. How quickly? Depends on how much overcurrent, and how well the tubes were made in the first place. And how cool the tube is kept while operating. I've read one treatise on tube life that says that high temps on the external glass is the biggest contributor to short life.

Sadly - it depends. A Champ isn't a high power amp and probably won't get hot stage use and regular trucking (with the ensuing vibration) every day or two, so they could well last some years or a decade or two.

Not the answer you're looking for, I know.

[Stevem]

In terms of the class A output stage that this amp has and output life in perticular ,the worst thing you can do is to leave the amp on and NOT play thru it!!!

The output tube in a class A amp is idling at a very high wattage and is dissipating that wattage thru itself until signal is pumped into it and then the voltage and current that produces that idle wattage amount is used to power the output transformer and then inturn the speaker.

In a way a class A output stage is like having your car's engine idling at 85 or more percent of the motors red line rpm!
Only once you put the in gear and drive does the screaming rpm's come down.