Letting a tube amp idle...Punishable offense?

Discussion in 'Tube Audio' started by bbqjoe, Feb 11, 2019 at 4:38 PM.

  1. bbqjoe

    bbqjoe Void where Prohibited Subscriber

    Messages:
    509
    Location:
    NW Arizona
    I don't think any of us would leave a tube amp on, then go on vacation, but, is there anything wrong with stopping a track to go do something for an hour or so and leaving the amp all nice and warmed up to come back to?
    Flame away!!! [​IMG]
     

     

    Please register to disable this ad.

  2. ic-racer

    ic-racer Super Member

    Messages:
    1,145
    Location:
    USA
    Yes, fire hazard.
     
  3. sKiZo

    sKiZo Hates received: 8642 Subscriber

    I always turn mine off after a session, mostly because otherwise I'll go off and forget to come back for a day or so ...

    More of an issue if like most of us, you don't leave proper clearance to dissipate heat. An idling amp can still generate a lot of that. It more than likely won't hurt the equipment, as I've known folk to leave em on 24/7 with no significant impact or degradation.
     
  4. bbqjoe

    bbqjoe Void where Prohibited Subscriber

    Messages:
    509
    Location:
    NW Arizona
    I should have clarified.
    I understand about electronic gremlins most likely striking when you aren't looking, but what I really meant to question, is it bad for tubes to sit all by their little selves with no signal to play with?
     
  5. sKiZo

    sKiZo Hates received: 8642 Subscriber

    I suppose being left with nothing better to do than play with themselves could at least get boring, or maybe cause blindness? ;-}

    Little to no impact on tube life though, at least in my experience.
     
    GuyNoir, 62caddy, gadget73 and 2 others like this.
  6. maxhifi

    maxhifi AK Subscriber Subscriber

    Messages:
    3,403
    Location:
    Edmonton Alberta Canada
    I don't see anything wrong with that - actually, I do it all the time.
     
    GChief likes this.

     

    Please register to disable this ad.

  7. solderjunkie

    solderjunkie Member

    Messages:
    59
    I once discovered a small hi-if amp in my son’s room had been on for over two weeks while he was away on a trip. No damage to tubes or otherwise, tho I gave him an earful when he returned!
     
  8. Lavane

    Lavane AK Subscriber Subscriber

    Messages:
    7,854
    Location:
    northern cal.
    An old friend had a tube radio in a pole barn that was left on the 24/7.
    It had been on as long as he could remember. His family lived on a ranch. He figured it had been left on for at leased 25 years. It, along with one lone light bulb only got shut off if the power went off. I spent a lot of time out at his place both day and at night. That radio was always playing.
     
  9. Dandy

    Dandy Super Member

    Messages:
    4,635
    Location:
    North West, UK
    Amazing. It makes me wonder if we are shortening tube life by powering off and on. But I'll still do that for safety..
     
  10. ehoove

    ehoove Old & New - Carpe Diem Staff Member Super Mod Subscriber

    Messages:
    18,593
    Location:
    Mid-Maryland
    I will leave SS gear on, but not tube gear
    Call me fire paranoid,
    Jim
     
    noogies, Rockyhill and Lavane like this.
  11. Rockon1

    Rockon1 Well-Known Member

    Messages:
    608
    I leave my guitar amps on for hours at a clip. I should add -not in standby since I'm told that's worse. Cathode poisoning. Bob
     
    Last edited: Feb 11, 2019 at 7:03 PM
    trainbuftony likes this.

     

    Please register to disable this ad.

  12. trainbuftony

    trainbuftony Electron Herder Subscriber

    I rebuilt a LK72 a few years back. My friend who ended up with it left it on for over a year... We played it at Christmas and it hadn't been shut off since last Christmas... Makes me nervous. Amp sounded great though.
     
  13. AdamAnt316

    AdamAnt316 Collector of heavy things Subscriber

    Messages:
    2,474
    Location:
    MA
    If all goes well, there's nothing strictly wrong with letting a tube amp idle all the time, except that you'll technically be using hours of the tube filaments' lifespans, and causing your electric meter to spin for no good reason. Some tube-based military radio gear like the R-390A was left on 24/7 to maintain stability, and they generally were very reliable. Also, as others have said, turning them on and off all the time has its own negative effects; early tube-based computers like ENIAC had issues with tube filaments blowing out all the time until they started leaving them powered up for long periods of time. Obviously, they could afford to pay the high electric bills associated with doing so.......... :rolleyes:

    However, if things don't all go well, you could experience a meltdown. This past fall, I powered up my Dynaco ST-70 in preparation for a listening session, and then called a friend on the phone. A few minutes later, while chatting with said friend, I heard some odd crinkling sounds from the ST-70, which was sitting nearby. I looked at the ST-70, and one or both of the EL34s in the right channel were red-plating! :eek: I quickly hit the power switch to turn off the amp; if I hadn't been in the same room, the tubes might've melted down, possibly taking one or more of the transformers with them. Since then, I've been very careful to not leave my vintage tube amps sitting unattended for long periods of time.
    -Adam
     
    a_retent, Harvestor, Dandy and 2 others like this.
  14. bbqjoe

    bbqjoe Void where Prohibited Subscriber

    Messages:
    509
    Location:
    NW Arizona
    I suppose that's one way to warm up an amp ahead of time. :)
     
  15. bbqjoe

    bbqjoe Void where Prohibited Subscriber

    Messages:
    509
    Location:
    NW Arizona
    I don't know what or where I read that led me to believe that it was hard on tubes to sit without a signal.
    Glad we have this cleared up.
     
  16. AdamAnt316

    AdamAnt316 Collector of heavy things Subscriber

    Messages:
    2,474
    Location:
    MA
    Sitting around without an input signal doesn't hurt tubes. However, being powered up without a load on the output(s) can sometimes cause an amplifier to go into oscillation, which is a Bad Thing.™ Melted tube plates, possibly toasted transformer innards, stuff like that. Also, as I said above, if something happened to go wrong with the amplifier while nobody was nearby to turn it off, similar things could happen.
    -Adam
     

     

    Please register to disable this ad.

  17. ducati_EL34

    ducati_EL34 Addicted Member

    How is VT equipment any more of a fire hazard than high current SS equipment? I am assuming that proper ventilation is provided.
     
    GChief likes this.
  18. Junk Audio

    Junk Audio Active Member

    Messages:
    210
    My tube amps are on 10 to 12 hrs a day every day during the work week, and sometimes idle for an hour or so with no issues. But I do like to have a main primary fuse, a B+ fuse along with speaker fuses...
     
  19. knockbill

    knockbill Addicted Member

    Messages:
    8,109
    Location:
    SE PA
    I've left guitar amps on overnight,,, panel for the 5C1 is on the back, and sometimes I don't notice the pilot... Forgetting its on maybe the only positive argument for allowing an amp to hum!!!!
     
  20. stanko

    stanko Hoarder Subscriber

    Messages:
    801
    Location:
    Oshkosh, WI
    PA amps were left on until they failed, then fixed and left on until they failed again.
     
    trainbuftony likes this.

Share This Page