How should you treat your tubes?

I had a thorough response written and I lost my Internet connection and my text.

Larryi: The VAC 140's have no means of powering up only the 6SN7's. The amp is either on or off, and I turn it off and on as needed. The 6SN7's are not a worry, however, as they are exceedingly hardy tubes that were primarily designed for use in televisions -- it is not unusual to get 40,000 hours out of a 6SN7. The comment in my owner's manual was about small signal tubes generally. Kevin Hayes of VAC is also quick to point out that the studies done in the 1950's established that small signal tubes last much longer and sound better if left on 24/7.

I might be reluctant to leave a tube preamp on that has a lot of tubes in the power supply (or that uses pentodes in the power supply like the ARC Ref 3 or big Jadis two-chassis or a really pricey tube like the 300B). I would be MORE inclined to leave a preamp having expensive NOS tubes in it powered up 24/7 precisely because such use tends to increase tube life.

For the record, I owned Jadis, CAT and Hovland tube preamps, and still have a CAL Audio Labs tubed DAC in the closet that I've owned since 1994. In a combined nine years of running those preamps 24/7, and another six years of running the DAC 24/7, I never lost a tube (the DAC sounded better than ever the last time I had it in the system) and only retubed the preamps when I sold them so that the new owners would have a component with brand-new tubes.

A little common sense goes a long way...if you are leaving the house, or there is a big electrical pull on your system from Air Conditioning or tools that you will be using, or a washer and dryer, sump pump, etc., or there is a thunder storm brewing, by all means turn off the amp first, wait at least 5 minutes, and then turn off the preamp. Under normal circumstances, turning the amp on in the morning and off when you go to sleep doesn't hurt the equipment and will add quality to your listening session.

Ekobesky,

It is a common myth that turning a light bulb on and off shortens it life.

There have been studies showing that turning your light bulb on/off numerous times per day (I can't remember the actual numbers in the test, but it was way more than you would ever do in real life) didn't decrease the life of the light bulb vs. just leaving the bulb on for extended periods.

Basically, it was proven that the light bulb will last longer if you turn it off when it is not needed and not to worry about the number of times it is turned on/off.

I don't know for sure if this also applies to audio tubes (especially NOS ones).

George

A final point: if you search the threads, you'll see that this subject has truly been beaten to death, as well as the more general subject of whether to turn equipment on and off or leave it on 24/7. In those threads, you'll see that repair techs and equipment manufacturers who contribute comments pretty much unanimously advocate leaving all equipment other than tube amps on 24/7 in the interests of longer component life and better sound. If you see the contrary in your owner's manual, it's for liability reasons -- the one component in a million that catches fire is going to result in a lawsuit for the manufacturer, so owner's manuals generally say "turn it off while not in use".

In response to one of the above posters, this is actually a case where the rejection of common sense and reliance upon the basic laws of physics is the way to go -- all matter, whether it is the concrete pavement of a freeway or a vacuum tube or silicon transistor in hi-fi gear, expands as it heats up and contracts as it cools down, and it is repeated expansion and contraction that compromises the physical integrity of these things over time. Keeping gear powered up keeps it at a relatively constant temperature, whereby there is little expansion and contraction -- the only downside in terms of component wear is that it can shorten cap life (capacitors are constantly being beaten by the oscillating 50 or 60 volt cycles of the electrical supply).

It is especially important to leave solid-state power amps and DAC's powered up 24/7. Naim, for example, says that it takes two days for some its amps to reach optimal operating condition (one of my dealers says "Naim amps need a week"). DAC's tend to sound like utter shit without lengthy warm-up (count on 24+ hours for most) and MUST be left on 24/7. I would add one exception to the solid-state amp rule -- Class A biased solid-state amps (e.g., Plinius or Gryphon) burn a hell of a lot of electricity and will turn the average room into a sauna if left on for long periods of time, and should be turned off when not in use as a result.

Of course you want to unplug hi-fi gear when there is an electrical storm or if you go out of town for two weeks, but for day-to-day, leave it on if you don't want it to break and if you want it to sound like the manufacturer intended.

I once watched one of my EL34 tubes 'flame-out'. I still have the wine stain that resulted from my "mad dash...".