(!!!) (#1 6072 from 1950's) 6072 GE NOS triple mica black plates "U" getter halo 1950's rebranded 12AY7 Ultron (2.5/2.8ma)
(!!!) (#1 6072 GE 1960) 6072 GE NOS triple mica black plates "O" getter halo 1960 era rebranded 12AY7 Ultron (3.4ma/3.7ma) (highest Ma and Gm)
(!!!) (#1 6072 PAIR from 1950's) JG-6072 GE NOS triple mica black plates "O" getter halo (59-39=1959) 1-2% matched
(!!!) (#1 6072 PAIR) JG-6072 GE NOS triple mica black plates "O" getter halo 1962 same date codes 1-2% matched
(!!) (#1 6072 5-Star PAIR) 6072 GE 5-Star black plates triple mica "O" getter halo NOS early 1960's (2.6/2.9ma and 2.7/2.9ma) 1-3% matched
(!!) (#1 6072 5-Star single) 6072 GE "5 Star" NOS black plates triple mica around 1960 (2.5/2.6ma) 1-2% section balance
(!!) (#1 6072 GE triple mica) 6072 GE NOS triple mica black plates "O" getter halo rebranded "12AY7 Ultron" circa 1960 1-2% matched (3.0/3.1 and 3.0/3.2ma)
(!!) (#2 6072 GE triple mica) 6072 GE NOS triple mica black plates "O" getter halo rebranded "12AY7 Ultron" circa 1960 (2.7/2.8 and 2.8/3.1ma)
(!!) (#3 6072 GE triple mica) 6072 GE NOS triple mica black plates "O" getter halo rebranded "12AY7 Ultron" circa 1960 (2.2/2.4 and 2.3/2.4ma)
(!) (#1 6072 single mid-1950's) 6072 GE black plates triple mica "square" getter halo mid-1950's tests like new - no printing on glass (2.3/2.6ma)
(!) (#4 6072 SINGLE) 6072 GE "5 Star" NOS black plates triple mica around 1960 (2.9/4.2ma) (recommended for guitar amp or mic preamp
6072 RCA NOS gray plates rebranded Sylvania 1960's (2.7/2.9ma)
6072 RCA NOS/75-80% gray plates rebranded Sylvania 1960's (2.1/2.4ma)
