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Vacuum Tube Break-in

Is there such a thing as tube break-in? I been laying with many tubes in about 20 tube amps for 40 years and never heard a difference in a new tube vs same tube with 50 hours use. I always bought and used NOS tubes, not used. I believe if a difference is heard with break-in, it is the placebo effect.

fisher_400
lak's avatar
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lak
4,532 posts
 

IMO everything has a break-in period but results heard vary depending on your listening skills and the component.

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drrsutliff
834 posts
 

I acquired a quad of Genlex KT88s for my VAC amp at one time to replace the factory tubes.  When I initially started using them I disliked the sound immediately and for the next 20 hours compared to the factory quad.  I ultimately swapped them out and put them away for a few months.  When I tried them again they were still not what I hoped for but suddenly over the next 10 hours they opened up and smoothed out. I thought I had given them enough time the first trial, but I eventually grew to really enjoy them.  Break in?  I don’t know, but many times there seemed to be improvement to be had in the first 20-40 hours of both power tubes and small signal tubes in my systems

apogeum
34 posts
 

The break-in period for tubes is real. At least 20hrs. but for true sonic improvement even more like 50 hrs or so depending on brand and tube.

If the tubes are new and not burnt-in before testing/matching them they will lose their closely matched condition after 20 hrs. The operation point and the plate voltage of the amp in which the tubes are used is an even more important factor for matching and how they will finally sound. Tubes should be matched for the plate voltage and quiescent current of the actual amp.Some companies do that (upscale audio as far as I know). Adjusting the bias after a while (if possible) is important.

 

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jjss49
6,610 posts
 

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

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