(!!!!) (Recommended Single) 6BL7GTA RCA NOS "D" getter NOS 1961 (33/37ma)
(!!!) (Recommended Pair) 6BL7GTA GE and GE branded Admiral 1960's (38/40ma and 35/45ma)
(!!!) 6BL7GTA GE branded Marconi NOS 1960 era tilted glass (46/53ma) (High Gm) strong single
(!!) (Best Value Pair) 6BL7GTA GE NOS and like new 1960's same build (41.5/43ma and 44/46ma) (Highest Ma)
(!!) (Recommended Pair) 6BL7GTA RCA NOS and like new 1960's (34/40ma and 38.6/39.8ma)
(!!) (Recommended Pair) 6BL7GTA GE "D" getter NOS 1950's same build (39/43ma and 41/40ma)
(!!) 6BL7GTA GE NOS "D" getter 1958 (43ma/53ma)
(!!) (recommended Pair) 6BL7GTA GE NOS 1966-1970 (47/50ma and 42/51ma)
(!) 6BL7GTA Tungsol "O" getter halo NOS 1960 era (38/43ma)
(!) 6BL7GTA Tungsol NOS 1960 era (34/36.5ma)
(!!!!) (Best Single 1951) 6BL7GT Sylvania wide tall black plates triple mica "D" getter NOS 1950-1951 (47ma/48ma) (1st series made)
6BL7GT Sylvania low hours 1953 D = rectangle getter halo long scratch on base (33.5/37.5ma)
6BL7GTA GE gray plates NOS 1974 (47/53ma)
6BL7GTA RCA coin-base NOS 1970's (31/32ma)
(!!!) (Best RCA Pair) 6BL7GTA RCA NOS 1966-1967 (36/37.5ma and 39/40ma)
6BL7GTA RCA NOS 1968 (32/33.5ma)
6BL7GTA Sylvania used/good 1960's (31/33ma)
(!!!) (Best Pair) 6BL7GTA GE NOS 1981 (36.5/38.5ma and 37.5/38.2ma)
