Vacuum Tube Break-in

there is always the conundrum with break-in/burn-in

is the gear or item burning in, or are we as listeners getting more accustomed to the sound over time, being exposed to it repeatedly? - we all hear our systems sounding different day to day, each time we turn it on... what we sense can vary, conditions can also change

age old question this is...

my sense of this, regarding tubes, is that for most well functioning tubes, they do take some time (in my view an hour to a day, or overnight) for their sound to stabilize, after that, our ears are also getting acclimatized, sometimes in a good way, sometimes not

@jjss49 So true in regard to listener acclimation period with any new component/variable being inserted into system. This especially true when I'm already contented with system sound quality.  My comfort zone is upended when something new placed in system, I'm in analytical mode which detracts from that comfort. Over time I can settle back into comfort zone, especially if change is positive. If change is negative, I find it hard to get back to comfort zone, in which case  I come to understand that particular change not good.

As for tubes, I find power tubes most sensitive to burn in, found at least 85-100 hours is time of great change.  Rectifier tubes sensitive as well, signal tube somewhat less. The fewer the tubes, the more I hear changes. SET, DHT especially sensitive.

                       For a few facts:

https://www.youtube.com/watch?v=jwmDf5bSRMQ

https://hometheaterhifi.com/editorial/oped/the-phenomenon-of-tube-amplifier-burn-in/

https://www.youtube.com/watch?v=Cs4fo8qJbio

SS stuff too:  https://www.youtube.com/watch?v=zResqsZngSU

It it’s on youtube, it must be factual.  you have posted a few opinions.  Beware of opinions.  And especially be aware of opinions from people who have something to gain from them.

    My first post to this thread was a quote from Brent Jessee.

     I doubt many would dispute his knowledge/claims, as regards vacuum tubes.

     Anyone that was interested enough to have checked my previous post would notice: my first reference was to an individual that showed how burn-in affects tubes, on a tube tester (iow: MEASUREMENTS).

    The next three, "opinions" were from well recognized equipment manufacturers.   I'll simply state that their experience mirrors my own.

    Denyin'tologists will never exhaust their reasons to dispute why, whatever the topic might be, won't/can't/shouldn't exist in this universe.

     Of course: the vast number of variables extant, as regards systems, room acoustics, source materials, ones listening habits/goals and (PERISH THE THOUGHT) aural acuity, must remain a non-issue in their belief system/doctrine/preaching.