Not sure of absolute life span, but tubes in general I would only run preamps for 24 hours before the weekend you will listen and shut off after that on a weekly basis, this will of course probably take 1 year off a tube that would maybe last 10 always shutting it off, but for running the system on a friday night and then again saturday afternoon etc... I would not keep shutting it on and off... Basically all a Standby switch does is Mute the output just like a mute button cutting the signal from feeding the amps if they are left on 24/7(solid state of course), so many manufactures use the Mute and explains to use it for not listening between listening sessions in 24 hour periods without shutting down and re-powering the unit several times. This in my opinion would be okay with use of Tube CD and preamps, power amps you would definatly kill off the power tubes and pull a lot of power sitting at idle faster and this would be pretty wastefull and of course more dangerous, so for an all tube intergrated I would probably suggest against it, but I'm no pro, this is how I see most hi-enders do it, and also how most the tube suppliers and manufactures have explained it to me as it will be fine for small signal tubes only.
Matrix - thanks for the response. I just want to make sure I am understanding you correctly - are you saying it IS okay for me to put my solid state integrated into standby and then power down my tubed CD player?
I generally keep my system fully powered for several days at a time and then if I'm not going to listen for a while I'd like to power down my tubed CD player but keep my solid state integrated on. My amp sounds better that way.
You can put the amp into standby, or you can mute the amp, or put it into standby or you can select a different input than the CD player before turning the CD player off. The point is that the CD player MAY emit a pulse when it is turned off which you would not want to amplify and feed to your speakers.
Most tube CD player outputs simply use the tube as a buffer. These small signal tubes would probably last LONGER if you don't turn the CD player off. Turning on a tube results in a quick inrush of current that rapidly heats the tube causing stress. This is what causes most of the damage to a tube. I would leave the CD player on all of the time. Also, when you turn the CD player off, the capacitors in the player discharge. It can take a lot of time for the caps to fully charge up and for the player to sound its best.
You'd better "Off"...
Don't ever live tubes on 24/7 or overnight. It realy doesn't matter if the tube will live longer or shorter it I guess matters to you more.
You can rely on circuit protection when the tube goes bad and you don't turn any tube component rightaway. If not you may set up your house on fire.
The safety issue is not limited to tubes. The tube itself won't start a fire, but the failure of the tube could casue other components to overheat and create a hazard. But, that is the case with solid state gear as well. Actual fires from component failure is not common, but I suppose there is some risk of leaving anything on all the time. Unfortunately, I do have to leave my refridgerator on all the time (but not, I suppose, the interior light).
From the Cary Audio website:
4. When is it best to turn my equipment off?
This brings us to an ongoing debate. Which is better-leaving the product on 24 hours a day or turning it on and off? Both will shorten the life of your tubes. So what should you do? The answer lies somewhere between the two. If you listen faithfully for several hours a day then leave the unit on. You do not want to turn it on and off several times a day. This is worse than leaving it on 24 hours a day. If you listen two or three times a week or just on weekends, turn the unit off when not in use. In this case, allow one hour for warm up time. For the weekend listener, turn the unit on Friday and turn it off Sunday night. This will optimize tube life for your amplifier. Preamplifiers and CD players should stay on all the time. The tube replacement cost for these units is considerably less than amplifiers. Most of our amplifiers have a Standby feature. The Standby is there to pre-warm the tubes before operating. Tubes generally last longer if they have only a few minutes of warm up time.
Most tubes will last for many years. Some will fail after a short period of time. As more tubes are being manufactured, the quality is excellent and the life is longer."
A refrigerator is less affected to fires than tube equipment.
Its life span is approximately 20 years and seing and also repairing older ones that, I've seen no fire damage.
Tube equipment has high voltages that could fry circuit board as a piece of paper. If you want me to show proof I can post photos of a PC board hole of an amplifier turned on 24/7 where just one EL34 tube went bad...
A similar "holes" I've seen when I repaired TVs but never I saw SS amp to have this kind of damage unless it's been used as a commercial DJ amp.
ANYTHING left on wears out. That is simple physics.
just turn in on 20-30 minutes before listening then shut it off afterwards. No sense in wasting the tube life when not listening.
I am not debating the merits of turning off tubed gear, but in conversation with Jud Barber of Joule Electra, he stated that many of his customers leave their Joule preamps on all of the time. In fact, he informed me that this was a perfectly acceptable practice with his gear and that the tubes should last 6-8 years following this routine.
There certainly have been some compelling reasons as to why this might be a dangerous or counterproductive practice but thought that I would relate another viewpoint that has been expressed from a well respected designer of tubed gear.
FYI, he did not say to follow the same routine with his amps however.
Been a tube guy for 20 years. I have always shut things down after each session. This refers to amps and pre amps./ My CAT has 10 tubes. To retube my CJ 8's is well over 1k. A one or 2 tube cd player would be best left on 24/7. Cost of retubing a CJ amp or CAT pre, being a big reason why I shut things down.
How's that for concrete anaysis. I had many of the best tube amps over the last 12 years and had an over abundance of tube failure. Probably 6-8 times per year!Some very dramatic with capacitors going as well. Most manufacturers always complain that its a bad lot of tubes and not their designs. The supposed best tubes are at a high cost especially matched. I went back to SS for these reasons.
I have a Joule Electra LA-100 MkIII and have left it on 24 x 7 the last couple of weeks while breaking in a new amp. In light of what Jud Barber says it will now most likely stay on, with the exception of extended time away from home.
On the other hand I would have never left my Cary V12i on all the time. I just never felt safe with the idea and could understand why Jud Barber does not recommend this practice with Joule amps.
Snook2 It's not a brainer to create a tube amp trouble-free i.e. if a tube goes bad nothing else goes bad(maybe B+ fuse) but along with that I would still be cautious leaving a tube equipment 24/7 even if the manufacturer is 100% sure.