How should you treat your tubes?

For a stretch of an hour or two, I would not turn off either, certainly not the preamp anyway.

Beyond that kind of time, a lot of different considerations come into play. Not only is the life of the tube at issue. Heat can damage other components, so leaving on tube gear, particularly if the tubes are enclosed or if you are dealing with hot output tubes, can result in shorter life for such components.

Other considerations include whether the equipment has "soft start" circuits (slowly brings up circuits so thermal stress on tube filaments are reduced) or if the power supply employs tube rectification (also results in slow turn on). With such slower turn on, the issue of wear from the turn on part of the cycle is reduced.

Probably the best answer would be that provided by the manufacturer.

Raquel,

That is interesting information from a manufacturer. But, how would one keep the small tubes (input, driver, phase splitter) of a power amp, like the VAC 140/140, on while the output tubes are not on? Does it have some sort of standby feature?

Also, while it is generally true that linestages have small signal tubes that don't degrade very rapidly under constant on conditions, that is not always the case. For example, the Counterpoint SA 3000 is pretty hard on tubes.

I might also be a bit leery about leaving on a linestage that had a lot of expensive small signal tubes in them (fortunately for me, my linestage uses cheap 12B4s for signal tubes). Still, I turn it off when not I am out for a long period of time. My phono stage has Telefunken ECC83s in it and uses two 300b tubes as rectifiers, I really hate to leave it on when not in use.