On average, how long do power tubes last in a tube amplifier?

Question

Eh?

Answer 1

I worked in a University language lab one time and we had a bunch of tube amps. They were on 16 hours a day, every day. As I recall, the TEch Dir had me change the tubes every two years, whether or not they needed it.

I only recall one failure--the plate had warped so much that it came in direct contact with the grid, causing a direct feedback loop, which melted the insides of the output transformer. Pretty exciting, with smoke, dripping melted insulation, the whole works. The tube was probably defective to start with.

Answer 2

Hi. Unfortunately there is no way of knowing when a tube will fail .That's why it is best to have spares. Also as a tube ages the sound quality begins to slowly deteriorate .so it is best to change them after they have been used for a long time
.Apparently,tubes from amplifiers improve in sound quality and longevity after they have been deep-frozen to around 200 degrees Centigrade (around -328 degrees Fahrenheit )
To avoid damaging the tubes,the temperature changes must be very very slow..