quote]What is the definition of "good"? Sonic quality? Durability? Given the longevitiy of some tubes (300b comes to mind) and unless a tube fails "early," it will be hard to prove that new tubes are predictably shorter-lived compared to older ones. Or am I wrong?[/quote]
A 'good' tube sounds good and lasts a long time.
A 'good' tube sounds good and lasts a long time.