[FullRangeMan]

I was told max. room temperature to run a hot tube amp is 25ºC or 63ºF. 
Do you think at this temperature the tubes last less than in the winter in your experience ?
Any other input about room temperature x tubes is welcome.
Thanks, Gustavo


> Never go to a psychiatrist, adopt a cat or dog from the street. On the streets pets live only two years average.

[Guy 13]

Hi all Audio Circle members.
Here in Vietnam in my living room it's almost always around 30C to 35C
(50 to 75% humidity) and my two tubes amplifiers
(Niteshade Audio SE 6L6 w/5U4 rectification and Decware SE84C+)
run so hot, that I don't take any chances and
cool them down with a table fan at low speed.

The power transformer is the one that get the hottest, I can hardly put my hand on it, well not for more than 5 seconds.

In my opinion and with my experience with electronics in HOT Vietnam,

I would recommend a room temperature not higher than 25C, not for the tubes themselves, but for the power transformer and capacitors.

My opinion.
Have a nice day.
Guy 13
 

[SET Man]

Hey!

    Really? If it gets above 63F the tube will burn or something.

    I don't think that would matter much for the tube amp. It is more likely that I will burn out first before the tube and the amp burn out in 63F+ room.

    You know I remembered growing up in Thailand. I remembered going to festivals at Buddhist temple and seeing tubes filled with so many tubes and usually I will see them put a small fan on it driving giant horn loaded speakers. The temp during summer there is 80-90F depend where you are.

    BTW... I usually have to turn on my window air con when I listen to my system with temp above 76-78F especially when it is also get too humid too. 

Take care,
Buddy

[zybar]

I was told max. room temperature to run a hot tube amp is 25ºC or 63ºF. 
Do you think at this temperature the tubes last less than in the winter in your experience ?
Any other input about room temperature x tubes is welcome.
Thanks, Gustavo


> Never go to a psychiatrist, adopt a cat or dog from the street. On the streets pets live only two years average.

Pure bunk!!

You can run a tube amp in whatever room you want (within reason) with no ill effects to the amp or its tube life.

However, a person may not like running a tube amp in a warm room.   

With my amps, I definitely have to have the AC on once the temp reaches the mid 70's to low 80's.

George

[sebrof]

I was told max. room temperature to run a hot tube amp is 25ºC or 63ºF. 

That doesn't even make sense. Nobody keeps their room that cool, so it's basically saying you can't run a tube amp indoors???

[rollo]

  All ya need is a dehumidifier. Not for anything but living in Vietnam you do not use an AC ?
  The reason IMO for that 63 degree temp. my be that hot tube amps is that it raises the room temp about 10 degrees and 72 degrees is the norm for us.
  My Audio Research DR 250 with 20 6550s [ 32 total] is a bitch in the summer. No AC in the basement and to date zero issues with tube life.
    The Cyber 211 SET amps with 1000V to the 211 as well have had zero issues. Humidity is more of a culprit than heat within reason. The Humidity will corrode internal parts and connections. My personal experience anyways.


charles

[S Clark]

A tube amp must heat an element to a certain temperature in order to emit electrons.  The cooler the environment, the more heat escapes into the room, and the more current the amp must use to heat the elements.  If anything, the hotter the room, the more efficiently your tube amp works. 
The "cool" room theory is bunk.

[wgscott]

That doesn't even make sense. Nobody keeps their room that cool, so it's basically saying you can't run a tube amp indoors???

But since 25°C = 77°F, at least it is giving you multiple options.   

[Goosepond]

You're right about 25C=77F. So where does the 63F come from? 

I can turn off all my gear, mostly SS, and run my AC 24/7 and it will never get down to 63F. 

Gene

But since 25°C = 77°F, at least it is giving you multiple options.   

[FullRangeMan]

Hey!
    Really? If it gets above 63F the tube will burn or something.      

Hi,
A tube had a ideal temp range, over this it will lasts less time/hours.
On too hot tubes some delicate metal elements can vaporize and will be collect by the getter.
I never see a tube datasheet inform the ideal temp range for a tube.
On the 90 years I read on a tube site the glass bulb can colapse/melt over the metal tube elements if the temp is high enough.

For this I like 6C33 and GM70 as the glass are the thicker I have seen, some say the Bendix brand also used a thicker glass, but I have never see any tube of this brand.
Regards, Gustavo

[FullRangeMan]

You're right about 25C=77F. So where does the 63F come from? 

I can turn off all my gear, mostly SS, and run my AC 24/7 and it will never get down to 63F. 

Gene

Sorry this wrong info. Seems the Celsius x Fahrenheit scales are not linear each other!!( Putz!).
According Digital Dutch: http://www.digitaldutch.com/unitconverter/temperature.htm
Celsius     Fahrenheit
1             33.8
10            50
40           104
45           113
100          212
So 25ºC = 77ºF

[Ericus Rex]

Tubes were developed and mostly used in an age without AC.  So if this theory it right it would mean tubes are unusable for most of the US for the entire summer and half of the year in the deep south.  Since the filaments get really, REALLY hot (I think around 1200C) I don't think the 20 or 30 degrees we humans live in makes much difference to the tube.

[FullRangeMan]

Tubes were developed and mostly used in an age without AC.  So if this theory it right it would mean tubes are unusable for most of the US for the entire summer and half of the year in the deep south.  Since the filaments get really, REALLY hot (I think around 1200C) I don't think the 20 or 30 degrees we humans live in makes much difference to the tube.

Good post, as Iam newbie in tubes Iam all ears.
Iam not shure if metal elements vaporize by external temperature or too hi volume control (excess power).
Gustavo

[richidoo]

The circuit design is much more of a factor on tube life than the ambient temp. But external cooling is a factor. So is # power cycles. Manley reported a customer with tube amps in a recording studio with cooling fans and leaving it on all the time tubes lasted much longer than normal.

[FullRangeMan]

The circuit design is much more of a factor on tube life than the ambient temp. But external cooling is a factor. So is # power cycles. Manley reported a customer with tube amps in a recording studio with cooling fans and leaving it on all the time tubes lasted much longer than normal.

OK, the ''circuit'' could be the B+ supply I think, a conservative power rate always help tube life.
The power on cycles is a issue indeed, looks inevitable anyway.
Thanks, Gustavo


P.S.> On the book ''Getting the mostout of VT'' by Robert Tomer there is a chart on page 100, suggesting Class A, low power amps lasts more tube life than Class B(PP);

[Poultrygeist]

Ever since one of tube amps over heated and went into protection mode I've used these tiny, very quiet HV fans. At Walmart they are under $10.

http://www.amazon.com/Massey-High-Velocity-Inch-Fan/dp/B00183PF76

[SteveFord]

Great tip on the fans - they're only six bucks a pop at Wally World so I just snagged four of them.
They work great.

Correction: 25% failure rate right off the bat, save your receipt.

[wgscott]

the Celsius x Fahrenheit scales are not linear each other!!( Putz!).

It is linear.  The conversion has an offset, because 32F = 0C, i.e.,

T(°C) = (5/9) * [T(°F) - 32 ]

[Steve]

Tubes have a maximum temperature of 250 degrees C, but some are lower, especially at the seals.

Of course resistors are usually conservatively rated so normal temperature rise should not affect life.

Electrolytic capacitors are temperature sensitive. A general rule is that the life expectancy is halved for every 10 degree C rise.

It is useful to keep transformer temperatures within reason. Warm to the touch seems reasonable to me.

Cheers.

[SteveFord]

I did discover that if you go overboard with cooling fans the amps never reach the designed operating temperature and the sound quality will drive you slowly insane. 
Once the small auxilliary fans were turned off the VTL magic returned.