(!!) (BEST SINGLE) 6DN7 GE branded RCA NOS 1960's (64ma and 7.2ma)
(BEST SINGLE) 6DN7 RCA NOS 1968 (38ma and 10.2ma)
(Best Single) 6DN7 Sylvania NOS 1960's (60ma/8.3ma)
6DN7 GE branded RCA NOS 1962 (46.6ma and 8.2ma)
6DN7 RCA Mexco coin-base same internals as Sylvania NOS 1970's (40ma and 8.5ma)
6DN7 Sylvania NOS 1970 era (39ma and 7.5ma)
