Leave tube amps always on?

Mark, the owner of Linear Tube Audio, suggested I leave my tube amps on all the time 24/7 if im listenting every day, and to turn them off if not using for a period of time, a few days or for example we go away.  His reasoning was that it uses considerable more energy to turn on/off on a regular basis. 

Do others agree?  Kinda risky since these NOS Mullard tubes ain't cheap and will soon be gone forever.   
Leave NOS on 24/7? Nah. Heck no. It’s not about money. It’s about scarcity.

If you are listening for an extended period of time, e.g. all day, then yes. Power up in in the morning, then power down at the end of the day or weekend.

NOS are expensive and more importantly--scarce. If you decide to leave on for 24/7, then roll out the rare valves/tubes.

I have two separate systems, and they are in different rooms. One is valve/tubed and the other is sand/solid state. I save the better (valve/tube) system for extended listening. The cheaper sand system monoblocks running the high-end Martin Logans I use and abuse almost daily, because I don’t care about their longevity.

ML informed me that the polymer nylon diaphragm has a very limited lifespan of only 15 years. So, I don’t and can’t care that much. I can "care-less" :)

Tubes do not "use" more energy at turn on or turn off.  That is NOT the basis for concern with turn on causing more damage to a tube than leaving it on constantly.  The concern has to do with two different issues.  The first is the stress from thermal shock.  When a cold tube is suddenly heated, the elements that are heated are stressed by the sudden heating and expansion.  That is why light bulb most often fail at the moment the light is switched on.  Tubes are subject to some thermal stress, but, it is not nearly as severe as with a light bulb.  Tubes are not made to heat up and start working as fast as a light bulb has to heat up and emit light. 

The second issue is what is sometimes referred to as cathode stripping.  If high voltage is suddenly applied to the anode before the cathode/heater has warmed up enough to be emitting electrons, the pull of the anode trying to attract those electrons can damage the cathode.

In a properly designed amp, the current should be applied slowly enough, and ideally, first to the cathode/heater circuit, and ramped up to avoid either concern.   Some tube units have such "soft start" circuits and utilize a relay that delays full power to the anode side of the tube.  My headphone amp has a circuit that takes a full minute before warm up is complete and the amp is operational.

Whether turning a tube on & off or leaving it on, a tube doesn’t consume any more power than they are designed to consume (as long as your amp is functioning properly and biased correctly). But the initial temp change from cold to hot when powering on is what is especially stressful on tubes especially power tubes.

Your LTA amp is designed to be less stressful on tubes thus longer life so I wouldn’t be as concerned with your amps. I would treat it like a preamp. Turn it off when you leave the house or go to sleep. Other times use discretion.

PS. EDIT: What Larryi2 said above while I was typing.
Nobody leaves tube amps on all the time turn on 1 hour before listing is enough.


Thx, super helpful explanation and information. A very knowledgeable forum.