Leaving tube amplifiers on all of the time?

[benherrmann]

Hello all...

Yes, I'm a "noob" to this forum, although I've been watching the audioholics videos for years now. I've been an audiophile for some 55 years, and one of the habits I've had was to leave my audio gear on all the time (mostly solid state amps, DAC's, etc.) - because I've discovered a long time ago that things sounded much better as time went on if you left the gear on. Now-a-days, my audiophile efforts are confined to a desktop, near-field scenario which suits me just fine.

A question I have involves tube amplifiers (mostly those using tubes in the preamp stage, with the amp stage being class AB or D). The question involves leaving those amps on all the time. Which will wear out tubes quicker - turning them on and off on a daily basis, or leaving them on all the time? In the past - when I wasn't paying much attention because I was involved with solid state only - some of the comments that I perused, emphatically pronounced that tubes "must" be turned off on a daily basis, otherwise the tube-life will be cut short, or the resultant heat can damage the other electronics. Some others, however, advanced the opinion that leaving tube amps on all the time on can't hurt, and the tubes can actually last longer.

What are your opinions here? I'm looking for some solid facts here...

Thanks in advance...

Ben Herrmann
US Marine Corps, Retired
Fuquay-Varina, NC

 

[TLS Guy]

Hello all...

Yes, I'm a "noob" to this forum, although I've been watching the audioholics videos for years now. I've been an audiophile for some 55 years, and one of the habits I've had was to leave my audio gear on all the time (mostly solid state amps, DAC's, etc.) - because I've discovered a long time ago that things sounded much better as time went on if you left the gear on. Now-a-days, my audiophile efforts are confined to a desktop, near-field scenario which suits me just fine.

A question I have involves tube amplifiers (mostly those using tubes in the preamp stage, with the amp stage being class AB or D). The question involves leaving those amps on all the time. Which will wear out tubes quicker - turning them on and off on a daily basis, or leaving them on all the time? In the past - when I wasn't paying much attention because I was involved with solid state only - some of the comments that I perused, emphatically pronounced that tubes "must" be turned off on a daily basis, otherwise the tube-life will be cut short, or the resultant heat can damage the other electronics. Some others, however, advanced the opinion that leaving tube amps on all the time on can't hurt, and the tubes can actually last longer.

What are your opinions here? I'm looking for some solid facts here...

Thanks in advance...

Ben Herrmann
US Marine Corps, Retired
Fuquay-Varina, NC

All the time the tube is on, it is wearing down. However it is a toss up if the heaters are LT AC. If the filaments are DC, then turning of is the best. However if the filaments have AC LT then are turn on the heater filaments get a jolt and it ends up what you believe. However, I think leaving tubes cooking is a hazard and a definite waste of energy, so I recommend turning gear off. I turn my gear off, and that is the sensible think to do. I do not believe this affects the sound.

And using tubes in the preamp stage is another fad, and frankly audiophoolery. The fact is a cheap $0.50 IC preamp chip has better performance, especially a better signal to noise ratio than any tube. preamp, and uses a lot less energy. It also does not heat up the surrounding electronics from "cooking" heater filaments.

Us older members grew out of tubes like we grew out of short pants. I will admit I do using one vintage tube preamp, a Quad 22, I bought in 1966. The reason I use it as the preamp for my historic Deeca/Garrard rig, as it contains all the EQ curves for pretty much all known 78 RPM discs.

LP

I certainly don't leave it on all the time. The unit does now have DC to the heaters, rather than the original AC. I don't have it there to convince myself it is superior to solid state gear, although it sounds very good, but it is part of the museum end of my collection, where tube gear belongs.

 

[benherrmann]

Thank you so much - a very detailed and technical response. This is what I need...

 

[Swerd]

… The question involves leaving those amps on all the time. Which will wear out tubes quicker - turning them on and off on a daily basis, or leaving them on all the time?

TLS Guy already answered your question, and I really don't have anything further to add to his response. But, your question does raise another point about audio. General advice or wisdom is often held over from the past, long after the time when it may have been useful. This is true for many things in addition to audio.

In the distant past, when all audio electronic gear ran with vacuum tubes, it was well known that vacuum tubes do warm up during the first minutes after you turn them on. No one seemed to know how much time warm up really needed, so just to err on the safe side, people recommended longer & longer warm up times. The longer the warm up time you believed was needed became an indication of how much of an 'audiophile extremist' you wanted to appear to others. The ultimate extreme audiophile solution was to always leave the gear on and fully warmed up. As TLS Guy pointed out, this can and does shorten the life of vacuum tubes. The enemy of all electronic gear, vacuum tube or solid state, is heat. Why heat them more than needed?

I used to work in biochemistry labs for many years. A common lab instrument was an ultraviolet (UV) light spectrophotometer. It used an electronic tube, filled with deuterium gas instead of a vacuum. When voltage passed through the plates, it emitted UV light. Like vacuum tubes, it had to warm up before it provided a steady source of UV light. If I had to use it, I usually switched it on the first thing in the morning. The general wisdom was to allow it at least 10 minutes to warm up. Of course, there were always those few people who wouldn't use the spectrophotometer unless it had been on for hours. But no one knew how much warming up was really needed.

Years later, I worked in a lab where there was an elaborate and very expensive UV spectrophotometer. It had built-in instruments that measured the temperature and voltage fluctuations of the deuterium lamp. Remembering that old warm up debate, I was surprised to find out that the deuterium lamp was all warmed up and ready to use about a minute after switching it on. Waiting 10 minutes was an excusable margin of error, but hours of warm up was silly overkill.

I know people today who keep their solid state audio gear on round the clock, fearing that cold circuits will harm the sound quality of their precious audio gear. It didn't really make sense back in the days of vacuum tubes, and it makes even less sense now.

 

[benherrmann]

All interesting points - thanks.

 

[fmw]

It is an expensive way to heat a room. Back my audiophile days I didn't leave them on or even give them a long warm up. They seemed to work OK.