I will add my point to NOS vs New Stock.
Tubes were made better years ago, and were more consistant than tubes of today.
Between China and Russia the specs are not as good, and there is a huge quality issue with both at times.
I do love JJ's, but truth be know. Tubes today last about half as long as the tubes of yesterday.
Mr.Slam and myself one day tested about 50 or so tubes on his tube tester. And if I remember right the NOS tubes tended to test higher on the tube scale overall.