RCA Grey Glass Hamburger Font 6SN7 - 1940's Production
Measured at my end by a friend and both close matched near Factory Spec's.
I have other pairs of Valve Types all matched near Factory Spec's. from the 50's and 60's Production Era's
oldest tube(s) in your system
Please let us know what they are running in too. Thank you for your attention to this matter...ha!
2 x 1949 Sylvania ladder plate 6BL7GT (in monoblock amps, custom built 2 x 6BL7GT + 4 x KT77)