Tube preamp, Leave On Always or ON/OFF?

I used to leave them on all the time. Now I turn them off as I got tired of replacing them often.

I have a BAT VK-50SE and I like to turn it off when not in use.

The BAT has a soft start feature, which gradually increases the voltage to the tubes over a period of time (about a minute). It drastically reduces the stress on the tubes during power on. Turning this kind of equipment on and off should not shorten the tubes life.

The BAT runs very hot. The heat it generates may shorten the life span of other components inside. Leaving it on all the time is going to dry up the capacitors sooner.

Not to mention the extra electricity it consumes.

But if you have a preamp that has no soft start feature, drives tubes gently, does not run very hot, and uses long lasting tubes; than by all means, leave it on.

Well, I'm glad to see this question was answered definitively. I understand the light bulb thing but I still can't see leaving tubes on 24/7 especially if they are NOS and you have paid big bucks for them.

I leave everything on but the TT motor. It shuts itself off after 40 minutes, which is great on drinking nights! All the tube stuff has good NOS tubes. I hate waiting for everything to get up to speed.

The proprietor of one of the high end's more noteworthy and successful tube gear companies explained to me that the studies done in the 1950's on tube wear all confirmed that small signal tubes, such as those used then and now in preamps and now in DAC's, tend to last much longer (and as a corollary, also sound better) if powered up 24/7. Basically, he said that, if left powered up 24/7, they either die at some point in the first 250 hours (infant mortality of sorts) or they basically last forever.

I leave all of my equipment except turntable and tube amps powered up 24/7. Over the years, this has included a tubed DAC (Cal Audio) and three tube preamps (Jadis, CAT and Hovland). In fourteen years combined of these tube components being left on 24/7, I have never had to replace a tube (nine years now on the DAC), nor has any of my equipment, tube or solid-state, required service. The only precautionary measure I take is to keep the volume turned all the way down (and the mute engaged for other reasons) on preamps so as to ensure that there is little current passing through the tubes when I am not playing music.

Tube amps cannot be left powered up because the output tubes pass a relatively large amount of current that stresses the tubes.

As a general rule, it is the thermal cycles that occur when equipment is powered up and down (i.e., repeated expansion and contraction of the components as they heat up and cool down) that kills components, even tubes - it is basic physics.