Tube pre-amps: turn off when not in use?

It could depend on the component and/or the manufacturer's recommendation.

When I owned a Kora Hermes DAC with two 6922 tubes I left it on coninuously for the four years I owned it without problem, even when fitted with NOS CCas, etc. But the tube preamps I've owned I always kept off when not in use.

The preamp I currently own uses two 6SN7 tubes and generates a decent amount of heat so I always turn it off. Plus the WWII era VT231s in that preamp won't last more than 6 months if left on all the time.

Both my tube amp and pre amp have a standby mode (thank god) which keeps them pretty toasty. When I fire up my rig: 30 minutes to sonic blast off. Otherwise I would probably be talking about 2 hours...

No matter what tubes will go faster turned on.. and preamps do draw a bit more than a dac or CD player and have more dangerous levels of heat in most cases.. Mine takes about 20 min tops to warm up and sound pretty much best after turning on.. this took about 100 hours of listening before it sounded that stable on new tubes however.. But short answer, turn it off, cause even if the tubes last for 4 years running 24-7, vs. only on for 2 hours 3 times a week will probably get you 10 to 20 years on the same tubes.

I leave my ARC LS 25 on during the listening months (Oct-May) since I listen pretty much every day. Since this preamp (and yours too) uses the 6H30 tube the 10,000 hour life equates to around a once a year change. Not too bad a trade-off for the always warmed up sound. Of course turning off after every listening session will increase life, but not as much as you would think since the turn-on/warm up process is a little harder on the tube compared to continuous operation.

Thanks for your replies. I do about 4-5 hours of listening a day so maybe switching off with use would be wise (or not?). For those who use tube pre with all-transistor based components (CDP, pwer amp), do you just turn off the tube pre while leaving all else powered up?