Mark, the owner of Linear Tube Audio, suggested I leave my tube amps on all the time 24/7 if im listenting every day, and to turn them off if not using for a period of time, a few days or for example we go away. His reasoning was that it uses considerable more energy to turn on/off on a regular basis.
Do others agree? Kinda risky since these NOS Mullard tubes ain't cheap and will soon be gone forever.
Vacuum tubes have a limited life span when turned on, whether playing music or not.
This is because the cathode element (the one that glows to throw off all those electrons used to amplify the signal) slowly wears out when turned on. The lifespan is usually expressed in the number of hours the tube is on. How many hours depends on the tube and how it is used in the circuit -- some amps push a tube harder than others. Power output tubes have a shorter lifespan than the smaller tubes used in preamps. The brand of tube is also a factor.
There are 8,760 hours in a year. If you have a power tube with an anticipated lifespan of 4,000 hours, you'll likely be replacing the tube twice a year if you leave it on 24/7. If you listen 8 hours a day and turn it off when not listening, you'll get over a year from the same tube. Listen 4 hours a day, an you'll likely get 3 years out of it. Different people look at ongoing maintenance expenses differently. You might want to ask the manufacturer of your amp about the anticipated lifespan of the tubes as used in your particular amp.
Per LTA's website "
we estimate tube life for our amps to be in the 10,000-20,000 hour range." Did they say what the tube life degradation from that level you'd experience if you turn it on and off as "normal" ?
Despite my question back to the aj523, I do agree with big-greg's & tvad'e No responses; I always switch my tube integrated amps, or tube preamp off when not in use.
Yes I thought I made that clear. Thats the suggestion from the designers themselves given the power surge in turning on and off multiple times. My healthy skepticism is questioning that.
I just can't get myself to leave my tubed integrated on all the time, even though a tech suggested I do it. It just doesn't sit right for this virtuous, right-thinking guy. To be honest, if it does indeed shorten tube life, so be it. It'll give me an opportunity to try out a different brand or model of tubes.
There are ways to gently turn on tube gear, such as a soft-start circuit, relays that apply full power to the B+ rail after the heater/cathode has been warmed up and emitting, etc. If a particular design is hard on startup, it really should be the designer's responsibility to use such measures instead of recommending that the owner waste electricity, prematurely burn up tubes, or increase the risk of damage to equipment and the home if something goes wrong with an unattended piece of gear.
Tubes, generally speaking, are NOT like light bulbs, so they do not suffer nearly as much from the thermal shock of being turned on. While tube gear might take a few minutes to sound its best after being turned on, that time is typically shorter than the warm-up time for solid state. It really shouldn't be the case that it is better to leave the gear on all the time.
The way I read it is his reasoning is based on environmental concerns and not the life of the tubes. I have had a Cat preamp for over 25 years and there is no difference in sound after 20 minutes of playing no matter how long it is left on. Based on that, I see no reason to leave them on for a minute more than when you are done listening for the day.
Leaving a tube amp on 24/7 implies that it will be left on unattended. If one of the tubes fails and the amp is unattended this could cause a significant fire hazard IMO. I would NEVER leave my tube amps or preamp on 24/7 under any circumstances.
I own 2 LTA amps now and I’ve also owned the LTA Ultralinear. These amps do run the tubes significantly cooler and stress them less than other amps using the same tubes. I’ve also talked to Mark several times at audio shows and he really seems to know his stuff.
I can see why he would recommend leaving them on because every time a tube amp turns on and off, that’s wear and tear on the tube. Even if it has soft start circuitry. An example, I have an older Modwright pre amp and the on/off toggle switch was damaged in shipping. I didn’t know that and when I started using it, the on/off switch made intermittent contact and rapidly shut the pre on and off a bunch of times. That quick series of powering up and down was enough to kill the rectifier tube and also F’ed up the driver tubes. Quickly turning tube amps on and off is really hard on the tubes.
That said, I wouldn’t leave the LTA amps on all the time either. If I’m just going out for an hour or so and I plan on listening when I come back, I’ll leave it on. But I wouldn’t leave them on for long periods if I’m not around. Too paranoid for that. They have built in protection circuits but my thought is, why risk it? I’d rather not have a fire happen that I could’ve prevented. Imagine trying to explain to the authorities what happened. “Yeah, I leave my tube amps running all the time... Oh, you don’t know what tubes are? They’re gas filled bottles that run hot and at high voltages.”
No matter the built-in protection, I take the point about gas filled tubes and fires and its enough convincing for me to shut it down every night or when we leave the house. Thanks for that gloriousunicorns :)
I guess it just comes down to some daily thought around when you may use your system throughout a normal 10 hour period in that day and plan accordingly 👌 So one follow up may be if I use my system on the weekends in the afternoon, take a few hours break and then again at night --- what say yee - on or off?
As a side matter, I have left my solid state amps always on 24/7 in my home theater room since 2011. And that was on the advice at the time of just about everyone on the theory that they draw very little power when idle and not being used and there is a bigger risk with the amp breaking down with constant switching on and off.
I don't own LTA, so maybe that is a very special case. Can't speak to it. In addition to fire hazard, tube life (both good points), my gear consumes over 100w when idle. I listen probably 2 hours a day, maximum, on average. This probably doesn't mean much, given the other factors, but at my electricity rates, the difference in energy use is $105 vs. $9. For decent tubes, that's the cost of about 2 tubes per year in energy savings. Over a few years, it would add up.
On the LTA website it mentions that they drive the tubes with 1/3 of the amount of current that typical tube amps use which is part of the recommendation. Also many believe that tube life is shortened because of multiple power up / power down cycles. Consider the physics of a cycle- abrupt current and heat to a cold tube and tube glass, thermal expansion differences between materials- e.g. glass and different metals and pins that are expected to hold a mechanical vacuum to survive. Running at temperature and maximum thermally expanded state for many hours then a rapid cool down / thermal shrink after power down. This happens every power up / run/ and power down. Thermally and mechanically stressful to the tube elements and glass.
Most tubes do seem to fail at startup as opposed to failing gracefully while running- similar to an incandescent light bulb.
I would consider leaving them on with an LTA product and see how it goes.
"Tubes, generally speaking, are NOT like light bulbs, so they do not suffer nearly as much from the thermal shock of being turned on." Actually; the cathode in a vacuum tube is heated by a refractory metal filament, generally tungsten, very much like a lightbulb’s. Some cathodes (directly heated) are the filament. https://en.wikipedia.org/wiki/Hot_cathode Even so; as much as I’ve spent on my NOS valves, persuading me to leave them on, 24/7, would be a difficult task. Glad my Cary monoblocks have separate B+ switches, so I can give the electrons time to start their hot little dance.
That’s the conundrum. The NOS Mullard Tubes, all 8 of them in my 2 amps ( a quad per) are EF2 from the early 1960s, are almost impossible to find outside of LTA and prices are over $200 per tube if you do. Even LTA acknowledges that unless they find another warehouse in Eastern Asia with 60 year old unopened boxes they will one day soon need to find a replacement tube for their zotl40 reference amp so I may not want to test Mark’s suggestion.
Today I will be watching football with the volume off,and listening to my main system which has a tube preamp. I won’t be leaving the house,so I will keep it powered up even if I go hang with the Mrs. before kick off.
His reasoning was that it uses considerable more energy to turn on/off on a regular basis.
Do others agree?
Uh, no. Not even other manufacturers. He should have done his math before saying something like that.
Now the amps probably take about an hour or two to sound their best; if this is the criteria (other than just simple warmup which takes 30 seconds) then the answer is still 'no'.
I dont need any more convincing. Mr. Berning’s ZOTL preamp/amp technology is mind blowing performance, like nothing I’ve ever experienced sonically and I don’t want that burn out faster lol.
Being an owner of ARC tube gear, my response is NO! My gear is probably 80% of the way there after 20 to 30 minutes after start-up. After an hour, my gear is all the way there.
I echo what another some of the posters said about tube life. My amp uses KT-150s, which are expensive power tubes that, per ARC, have a service life of 3000 hours. Too darn expensive to leave my gear running 24/7.
I am also concerned about energy costs and even safety.
The arguement for leaving tubes on is that they sound better fully warmed up not that the tubes consume excess power when you turn them on. Frequent on off tends to reduce tube life especially power output tubes.
You should perform some experiments by listening to your LTA amp from a cold start vs fully warmed up. Can you hear a difference? What is the minimal acceptable warm up time? Please report back what you find.
Hi thx for the reply. Do you have an inconsistency in your first paragraph? In the first instance you said tubes don’t consume excess power when turned on, then you follow up with the constant turning on/off shortens tube life. Arent those two statements binary? Anyway, what you said is exactly what the engineer who built the amps said-- "frequent on /off tends to reduce tube life so leave them on"! That has the added benefit of keeping them warmed up all the time.
Leave NOS on 24/7? Nah. Heck no. It’s not about money. It’s about scarcity.
If you are listening for an extended period of time, e.g. all day, then yes. Power up in in the morning, then power down at the end of the day or weekend.
NOS are expensive and more importantly--scarce. If you decide to leave on for 24/7, then roll out the rare valves/tubes.
I have two separate systems, and they are in different rooms. One is valve/tubed and the other is sand/solid state. I save the better (valve/tube) system for extended listening. The cheaper sand system monoblocks running the high-end Martin Logans I use and abuse almost daily, because I don’t care about their longevity.
ML informed me that the polymer nylon diaphragm has a very limited lifespan of only 15 years. So, I don’t and can’t care that much. I can "care-less" :)
Tubes do not "use" more energy at turn on or turn off. That is NOT the basis for concern with turn on causing more damage to a tube than leaving it on constantly. The concern has to do with two different issues. The first is the stress from thermal shock. When a cold tube is suddenly heated, the elements that are heated are stressed by the sudden heating and expansion. That is why light bulb most often fail at the moment the light is switched on. Tubes are subject to some thermal stress, but, it is not nearly as severe as with a light bulb. Tubes are not made to heat up and start working as fast as a light bulb has to heat up and emit light.
The second issue is what is sometimes referred to as cathode stripping. If high voltage is suddenly applied to the anode before the cathode/heater has warmed up enough to be emitting electrons, the pull of the anode trying to attract those electrons can damage the cathode.
In a properly designed amp, the current should be applied slowly enough, and ideally, first to the cathode/heater circuit, and ramped up to avoid either concern. Some tube units have such "soft start" circuits and utilize a relay that delays full power to the anode side of the tube. My headphone amp has a circuit that takes a full minute before warm up is complete and the amp is operational.
Whether turning a tube on & off or leaving it on, a tube doesn’t consume any more power than they are designed to consume (as long as your amp is functioning properly and biased correctly). But the initial temp change from cold to hot when powering on is what is especially stressful on tubes especially power tubes.
Your LTA amp is designed to be less stressful on tubes thus longer life so I wouldn’t be as concerned with your amps. I would treat it like a preamp. Turn it off when you leave the house or go to sleep. Other times use discretion.
PS. EDIT: What Larryi2 said above while I was typing.
BS, it absolutely does not cost you more energy to turn your tube amps on an off relative to leaving them on all the time. Tube life is shortened but not as dramatically as you would think. I do know some people who keep them on because they hate waiting for them to warm up. They are also filthy rich and could care less about tube life. Some tube units like my ARC phono amp have low power standby modes. I do leave that on continuously. I have a class AB SS amp in the workshop that I leave on all the time but the JC 1's in the main system are turned off. Turning the tubes on and off stresses the filament due to expansion and contraction of the metal with the extreme changes in temperature. Same for transistors although the temperature changes are not as extreme.
Two years ago I asked Kevin Deal, Upscale Audio at the RMAF show (Denver) should you leave an integrated amp on 24/7 or only when needed. His expression and definitive answer was "Only on when you use it!"All my integrated amp's tubes still sound good today. I just occasionally clean their pins. :-)
My wife left my Rogue tube amp and pre-amp system on all of the time and it was expensive both in tube replacement and utility expenses. The big amp was like a fireplace! I sold the whole system and replaced it with an Exogal digital power DAC combo and never looked back. The new components sound fantastic, take up very little space, and are cutting edge modern audio design. In my opinion the tube thing is greatly overrated and the tube sound is a likable form of distortion.
@rtorchia Glad you found something you like better. If you like the sound and looks better, that's good enough reason to change. But if the only reason you got rid of your system was because it was hot and awkward, it's clear (a) you could have just turned your system off when not in use and (b) there are other more compact systems using tubes, including by Rogue, such as the Pharaoh. Just adding that for anyone who doesn't glean that your change was not forced by the options out there. There are options out there.
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