Leave tubes on all the time?

Discussion in 'Audio Hardware' started by audiorocks, Nov 17, 2014.

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  1. audiorocks

    audiorocks Forum Resident Thread Starter

    Location:
    California
    Does leaving a tubed component "on" all the time shorten the tube life or do you have to be playing music through them to wear them out?
     
  2. whaleyboy

    whaleyboy Senior Member

    Location:
    San Diego, CA
    I have always understood that just having them turned on consumed their viable live span - music or no - so when I was using tube gear I followed Conrad Johnson's suggestion of turning them off if they were going to go unused for an hour or more.
     
  3. chervokas

    chervokas Senior Member

    Personally I don't think it's terribly safe to leave tube gear on unattended forever. I've seen too many resistors fail, tubes start red plating, or contemporary production tubes otherwise fail spectacularly over years of using tube hifi and guitar gear. For me, for safety's sake, I'm much more comfortable just letting the gear warm up a bit before listening. Using a tube is going to shorten it's life -- like a light bulb -- regardless of whether or not you're playing music. It's also possible that turning 'em on and off more frequently is going to shorten their life. Or the heat from the tubes being on all the time will shorten the life of nearby circuit boards or parts or something. Tubes definitely don't live forever. But for me I'm more comfortable knowing that the tube gear is off when no one is around or using it.
     
  4. Scott in DC

    Scott in DC Forum Resident

    Location:
    Washington, DC
    I turn them on during the time when I am listening and then turn them off for the evening. I don't leave home with the tubes on and I am in the same location as my audio system while they are on, except when I get another beer.

    Scott
     
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  5. vinylkid58

    vinylkid58 Forum Resident

    Location:
    Victoria, B.C.
    I leave my preamp on all the time, mostly it's unintentional. I NEVER leave my amp on when I have to go out.

    jeff
     
  6. Edgard Varese

    Edgard Varese Royale with Cheese

    Location:
    Te Wai Pounamu
    The manual for my Little Dot amp says not to run the tubes for more than 8 hours at a time.
     
  7. Gary

    Gary Nauga Gort! Staff

    Location:
    Toronto
    Turn them off!
     
  8. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    Depends.

    Small signal tubes, such as those in a pre amp or in the output stage of a CD player have a very long life span and are safe to leave on all the time. For example, the pair of tubes in one of my CDP's were on 24/7 for 8 years without issue and still tested good when I took them out to try a different brand. Another example, the signal tubes in one of my tube pre amps, even in standby mode remained on, only the power tubes were turned off.

    Power tubes, which have a much shorter life span, are different story and should never be left on unattended for any length of time.
     
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  9. EasterEverywhere

    EasterEverywhere Forum Resident

    Location:
    Albuquerque
    I would be interested to know how many of you have tube amps that do not have a dedicated on/off switch,neither of mine do.So how do you turn them off? I have my amps plugged into surge protectors.Is it bet to unplug them,or just switch off the surge protectors?I have been known to do both.
     
  10. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    I don't recall seeing a tube amp without a power switch, althought sometimes they are on the back. What do you have?

    On another note, it's best to plug amps straight into the wall instead of a surge protector as they can be a choke point. This is especially true of the strip type surge protectors.
     
  11. c-eling

    c-eling They're made of light,We never would have guessed

    Does this include 5670 tubes also?
     
  12. TLMusic

    TLMusic Musician & record collector

    In my experience, it's unsafe to leave power tubes on unattended.
     
  13. inperson

    inperson Senior Member

    Location:
    Ohio
    I first tube amp got heavy use. It was a diy amp made by some guy in Beijing, 6L6 PP. I never turned it off. I swear it was on for months at a time. At that time I knew nothing about tube rolling and just used cheap Chinese 6L6's. They lasted a long time. Nothing ever exploded or red plated but when the tubes were starting to go they had distortion and some noise, at that time I simply replaced a tube. I never replaced quads, just one tube if it was going out. I even took the amp to the maker and had him bypass the bias adjustments. I used it hard. I still have it but rarely use it anymore. But now I turn my tube amps off, I don't want to take a risk. In China the apartments were made out of solid cement so I didn't worry about fire but in the US it is something to consider.
     
  14. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    I'll take it you are using it in a pre amp gain stage, so fine to leave on
     
    c-eling likes this.
  15. inperson

    inperson Senior Member

    Location:
    Ohio
    Really? I never heard that before.
     
  16. F1nut

    F1nut Forum Resident

    Location:
    The Mars Hotel
    You'll find most amp manufacturers recommend straight to the wall.

    Those strip protectors are a joke when it comes to audio. A cheap switch, junk outlets, a couple of MOV's and thin wire.
     
    rbbert likes this.
  17. audiorocks

    audiorocks Forum Resident Thread Starter

    Location:
    California
    My integrated amp uses 12AX7s or 6922s (switchable), my DAC uses a 12AU7, and my phonostage uses a 12AU7 and 12AX7s. It sounds like it's OK to leave all this stuff on all the time, both for safety and for tube life? No danger of fire with these?
     
  18. JBryan

    JBryan Forum Resident

    Location:
    St Louis
    Any tube can experience catastrophic failure and that can take out fuses, resistors, caps or ruin the power supply.... it can also result in a fire. The simple answer is to not leave tubes unattended. There's a rule of thumb which suggests that you should never leave the room for the 1st 10 minutes after powering up tube gear. Usually, if anything goes bad, it'll happen soon after flipping the switch and once the tubes are stabilized, failure is much less likely.

    Small signal tubes have longer life and there are folks who think that turning on gear from a cold start shocks the plate and strips the cathode doing more harm and shortening the life than leaving the tube on (much like an incandescent light bulb). A good option that quite a few builders incorporate into their designs, is a 'stand-by' switch. This applies a trickle of power to the tubes - no shock or stripping and the 'warm up' time is much reduced. I have an old tubed DAC that has been on stand by since I started using it save for a handful of times that I needed to shut it down (storms, long vacations). I installed a used pr of Telefunken 12AX7's last century (pre-2000) and they're still going.
     
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  19. moops

    moops Senior Member

    Location:
    Geebung, Australia
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  20. Larry I

    Larry I Senior Member

    Location:
    Washington, D.C.
    NO. It is not recommended for reasons of safety, tube life and life of other components to leave tube gear on all of the time. The cathode of a tube has a limited life, why use it up wasting electricity? Most tube gear do not need to be warmed up for a very long time to sound good. Solid state gear takes more time to warm up so it might make sense to leave solid state gear on for long periods, but, this is not necessary for tube gear. If the tubes are putting out enough heat to warm the amp up appreciably, that heat is also shortening the life of other components, particularly capacitors and resistors (go to any specification sheet for these components, there is a different life rating for different temperature of operation). Small signal tubes tend to last longer so one might be tempted to leave linestages on all of the time, but, not all equipment run such small tubes conservatively enough that one will get decades of service. I know of some brands that have to be retubed once a year if used heavily. I can see how a simple buffer in a DAC can last for a VERY long time if it is run conservatively, so there might be a sonic reason to leave a tube DAC on all the time (the rest of the circuit could take a long time to warm up if it is shut down), but I would not do that myself with a tube DAC that has multiple tubes used for analogue stage amplification.

    Tubes are not like light bulbs in that their filaments do not heat up as quickly so they are not quite as prone to damage from and shortened life from being turned off and on frequently. However, they are prone to cathode stripping, as Byan mentioned above, which comes from the plate voltage coming up well before the cathode heats up enough to be emitting; this does shorten life. This is more of a problem with tube gear that has solid state rectification if there is no soft start or other protective circuitry. If one is really concerned about this, the manufacturer should be consulted about what protection is built in or whether some form of protection can be added, such as a thermistor in the power line to slowly ramp up current flow, or a standby switch that allows one to apply full plate voltage after first allowing the filament to heat up and the power supply to settle down (my linestage is designed that way).

    One more thing, when you do turn off tube gear, give it a few minutes before turning it back on. I have noticed that some gear will behave badly if turned back on shortly after being turned off (the rectifier on my amp will emit a bright flash, a friend's amp puts out very loud noise).
     
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  21. chervokas

    chervokas Senior Member

    I wouldn't say "no danger of fire." I mean, I've never seen such a fire or failure, but I don't like to think such a thing can never happen. Let's say much less likely to have catastrophic problems that could result in such a problem. I haven't seen that sort of thing happen with a preamp and small signal tubes only. But personally I'm of the opinion that there's no advantage to leaving the tubes on all the time and only disadvantages -- you are using up tube life during long idle stretches; I've never been of the belief that there's an enormous sonic difference between equipment allowed to warm up, say for 20 minutes or enough time to come to thermal stability, and equipment left on 24/7; and there always is a risk of failure resulting in fire, even though I've personally only seen those kinds of failures happen with rectifier and power tubes, not small signal tubes; not to mention whatever environment negative impact results from wasting energy by powering up the tubes with high voltage when you're not using the gear.
     
  22. audiorocks

    audiorocks Forum Resident Thread Starter

    Location:
    California
    Thanks guys, I'll start switching em off from now on. My integrated amp and phonostage go through two stages after being turned on which must be protection against cathode stripping, but I'm not sure about the Wavelength Brick DAC. I'll check with Gordon.
     
  23. inperson

    inperson Senior Member

    Location:
    Ohio
    Just let the amplifier's fuse take care of protection?
     
  24. reb

    reb Money Beats Soul

    Location:
    Long Island
    If the tube component is on, then there will be hours of usage deducted from the specified life expectancy of said tube.
     
  25. seed_drill

    seed_drill Senior Member

    Location:
    Tryon, NC, USA
    I've occasionally forgotten and left the things on overnight or while I went away, and always get my "that was stupid" feeling, like leaving the drier running while there's no one home
     
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