said above by Fletch >>>"But it only takes to look at a tube, and see the same internal construction, to know that there are no differences>"
Can you really do this????
If you can just look at a tube and do a visual inspection and see there is no difference then why go to the trouble of an electronic tube tester and matching?
There can be small differences in tubes of the same type and even the same run. This is just part of what they are and the tolerances involved and the production process. My understanding is that some tubes used in some critical military applications (Mig fighters etc...) were subject to much higher testing and Q control. I was also told that one reason that some old tubes are so good is that they threw so many away in the QC testing. Making tubes was apparently a process where a good portion of the runs went straight into the bins. This makes a certain amount of sense.
To the extent it is true I cannot say.
It may also be true that for some/many audio applications it may not make a big difference.
Sincerely
I remain,
Can you really do this????
If you can just look at a tube and do a visual inspection and see there is no difference then why go to the trouble of an electronic tube tester and matching?
There can be small differences in tubes of the same type and even the same run. This is just part of what they are and the tolerances involved and the production process. My understanding is that some tubes used in some critical military applications (Mig fighters etc...) were subject to much higher testing and Q control. I was also told that one reason that some old tubes are so good is that they threw so many away in the QC testing. Making tubes was apparently a process where a good portion of the runs went straight into the bins. This makes a certain amount of sense.
To the extent it is true I cannot say.
It may also be true that for some/many audio applications it may not make a big difference.
Sincerely
I remain,