here is my conclusion...
tubes do not break-in they start to work out their life time just from the moment you turn your amp(s) on. within the time to the end of tube life tubes sound dull and mushy and certainly need to be replaced.
next thing you do is you change tubz and certainly you need some time to adopt to them since they do sound different from your previous setup and certainly brighter. within "n" hours you will get used to it.
tubes do not break-in they start to work out their life time just from the moment you turn your amp(s) on. within the time to the end of tube life tubes sound dull and mushy and certainly need to be replaced.
next thing you do is you change tubz and certainly you need some time to adopt to them since they do sound different from your previous setup and certainly brighter. within "n" hours you will get used to it.