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Tube break-in?

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Does tube break-in exist? Obviously they age, but is there a period where they get "better"? If so, in what way "better".
I bought a bass amplifier with a 6205 in the pre amp. Yes I know that its not a "real" tube like a EL84 or a 12AX7, and its not the reason I bought the amplifier. I'm just curious.

P.S. its hard to search on a word like "break". Sorry.
 
tubes simply change over time.

one might say that they sound worse as it happens, others might say they sound better.

Remember, you are talking about your musical instrument: however it sounds, as long as the circuits work properly (and maybe without this restriction either!) it is the sound of your instrument. If you don't like the timbre it has, what does it matter if the tube is broken in or not?
 
i googled your first sentence......tube break-in exist - Hanapin sa Google
The first entry is THIS thread. The second is a mirror of this thread. There are no other relevant entries. Thank you for repeating my point.

tubes simply change over time.
Which I also stated.

I understand that tubes degrade. What I was asking was if tubes have an initial period (minutes / hours / days) where they reach their best potential.
 
tubes have life span ratings, some 1000 hours others have more....

i thought post#2 have summed it all...

you must have been reading audiophool literatures.....read the datasheets for tubes instead, see if you can find something there....

but tubes degrade each time you power them up and once you start using them, so i don't know what "reach their best potential" actually means....

sorry, can't help you there.....
 
The first entry is THIS thread. The second is a mirror of this thread. There are no other relevant entries. Thank you for repeating my point.

Which I also stated.

I understand that tubes degrade. What I was asking was if tubes have an initial period (minutes / hours / days) where they reach their best potential.

well, they need some time to warm up. my 15W laney takes all of 10 seconds to do that (15 in the winter). more powerful amplifiers take more time.
 
People seem very dismissive bordering on the aggressive, because I asked a simple question.

and its not the reason I bought the amplifier. I'm just curious.

Its a THING. Things are designed to do a job. Thing need a while to settle down. For an engine that's 500miles. For a speaker it can be 10 hours. A tube? could be milliseconds could be hours. I didn't know. I came to a specialist forum to find out. It does not mean that I want a particular answer. Just asking.

It does not matter

Calm down

Goodbye. Unsubscribed.
 
"reach their best potential"

okey, from a purely technical pov. tubes reach their working potential several seconds after switch on every time you switch on your amp.......

this is because the filaments need time(several seconds) to reach their working temperature for the cathode to start emitting electrons and for the plate to start drawing plate current....
 
it depends on the tubes. some sellers and reviewers of tubes report that the tubes sounded better after X amount of hours of use. There could be a lot of different reasons for this....for example...new tubes waiting to be sold will start to emit gas from their internal metals....the degree of gas vary's based on composition...so upon first use the tubes have some gas in them...after a few hours the heating of the getter starts the process to absorb the gas....so now you have a gasless tube which will sound better than the tube in it's original state. So how many hours...that depends on the heat which is a factor of bias current , enclosure type and even the positioning of the tubes...tubes installed upside down as in guitar amps will tend to become even gassier as they are used since it's harder for getter to heat up while the tube is upside down.
 
I didn't know that radiation knew the difference between up and down, or conduction either for that matter. It might even be argued(although I won't!) that because the getter is highly reflective,reducing the radiative heating nearby, then glass in the region of the getter can cool more effectively by convection if it is at the top and there will then be a greater temperature gradient over the glass envelope. I agree with the thread starter; some rather dismissive replies. DF96 seems, as usual, to have addressed the most important issue in post 2.
 
I know of several companies that burn tubes in for at least 24-48 hours when new. I have seen first hand that the tube's specs can and will change drastically during this time! the amount depends on the tube, brand, voltage etc etc. But think about it. the filament is burning off any impurities on its coating and within the tube, the getter is collecting those impurities plus as the tube heats up everything is expanding and out gassing etc etc. In fact as you power cycle the tube the first few times all that metal expands and contracts inside. I'm sure it takes a while for a tube to settle in! after a period of time the filament can develop hot or cold spots, the grid can shift. etc etc.
 
If you believe in break-in as it's commonly discussed and described, how would you tell the difference between tube changes and the whole rest of the circuit changing unless you were installing a new tube? My guess is any good tube manufacturer runs the tubes long enough to reach some degree of stability, and then they pretty much degrade from that point on. It's an extremely slow process unless the operating conditions are aggressive.
 
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You guys did a pretty good job scaring off the OP, and (some of you) obviously have not measured the significant change in transconductance that occurs (depending on type) over the first few minutes of operation from cold.

Tube manufacturers in times past burned in tubes to stabilize operating parameters and to weed out early failures or devices likely to fail spectacularly. Given the lack of aging at the manufacturer these days it is quite possible and IMHO likely that a good new tube will suffer some parametric shifts during the first hours of operation. Horrors, in a zero feedback design this might be audible, and horrors, even measurable. :p

There may be some shift during the initial hours of operation, not to mention a general level of discomfort I personally have with most modern power tubes for the first few hours of use. (As evidenced by a need to reset the bias repeatedly in some instances for the first 50 hrs or so of operation, and the occasional unwelcome, spectacular failure.)
 
All cold tubes need a time to the cathode warm-up, before the tube may receive the grid and B+ tension, this time are various minutes not seconds, if long tube life is desired.

For the 6C33 the Michael Boelle datasheet say in the small letters that in the military use the minimum time are 120 seconds, and the regular time are 600 seconds(10 minutes), but this is on military use where prompt working is need, there is no money restrictions and these tubes are specified time life in 1K hours by the factory.

In Hi-Fi use the regular time to heat the 6C33 cathode before may receive the Grid & B+ hi voltage may be 20 minutes minimum, but I never see any amp doing it, most have just 1 power on switch and only a 5 seconds soft start, where after it the cold tube already receive the all the 3 suplies, cathode heating, grid and B+, resulting in short life or tube damage along the way.

The Almarro 318 sports a 120 seconds clock delay, Almarro also inform is need monitor/adjust the 6C33 Bias every hour in the firsts 100 hours of this tube as the Bias is manual for best sound quality.
Joule-Electra OTL amps use a Variac to slow power on and claim a 5K hours time life for the 6C33 tubes.
Atma-Sphere do the right thing in its amps and put 2 power on switches, one for heat the cathode other for grid & B+.

Factory tubes usually no inform this heating times in its sites as they want sell alot of tubes, so no one builder remember this detail.
Hope this help.
 
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A tube becomes more microphonic with age - mainly I reckon due to reduction in clamping of mica to the glass wall. Maybe the change in 'sound' that some people observe is a changed level of microphonic addition to the sound they are hearing overr time. Per se, this has no relation to electrical parameters that are normally seen changing with other time-scales.

Different tubes have different levels of microphony, and the character of the microphonic contributions may be quite different, which may also lead some to characterising the sound of a tube as different from another - but that's another argument for another thread.
 
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