Gary,
I know, 40K hours is hard to grasp.As Brf pointed out however this tube was designed for very long and trouble free use fot telephone line service. This was meant to be from the outset an ultra low maintenance service tube. What is critical is how meticulously the various current 300b tubes are made.Suppositly this is a design objective by the Japanese engineers assigned to the Takatsuki project.The tubes are too recently developed to know yet their longevity. I can only attest to superior sound at this stage.
Regards,
I know, 40K hours is hard to grasp.As Brf pointed out however this tube was designed for very long and trouble free use fot telephone line service. This was meant to be from the outset an ultra low maintenance service tube. What is critical is how meticulously the various current 300b tubes are made.Suppositly this is a design objective by the Japanese engineers assigned to the Takatsuki project.The tubes are too recently developed to know yet their longevity. I can only attest to superior sound at this stage.
Regards,