(!!) 12AX7A Westinghouse pinched plates "D" getter used/like new early 1960's no printing (Gm=1600/1750)
(!!) 12AX7A Westinghouse pinched plates "square="D" getter" used/good 1950's (Gm=1400/1650)
(!!) 6BL7GTA GE NOS "D" getter 1958 (43ma/53ma)
(!!) JG-5814A GE NOS 1965 (9/10ma)
(!) (Best Single) 407A Western Electric tests like new 1960 (42/26 and 50/26)
(!) 12AT7 RCA black plates NOS D getter halo 1950's, slightly microphonic (13/16.4ma) (high Ma and Gm)
(slightly microphonic tube) 12AT7 Brimar UK black plates "D" getter halo copper grid posts used/good 1955 era (7.2/8.4ma)
(slightly microphonic tube) 12AT7WA=CV455 Mullard NOS "curved D getter halo" copper grid posts 1959 perfect printing (8/9ma)
(slightly microphonic tube) ECC81=12AT7 Mullard NOS "curved D getter halo" copper grid posts 1955 (9.2/10.6ma)
(slightly microphonic) 5687 Raytheon black plates NOS "square" getter halo 1950's (37/39ma) (strong Ma and Gm)
12AT7 Siemens Halske Germany D getter NOS 1957 (6ma/8ma)
12X4 CBS NOS black plates "D" getter 1959 (48/40 and 48/40)
12X4 GE gray plates "D" getter NOS 1960 (50/40 and 50/40)
407A LM Ericsson Sweden like new 1960's (41/26 and 42/26)
407A LM Ericsson Sweden used/good 1960's
407A Western Electric like new 1968 in white box (54/26 and 64/26)
407A Western Electric used/good 1959
407A Western Electric used/good 1967
407A Western Electric used/good 1972
6BL7GT Sylvania low hours 1953 D = rectangle getter halo long scratch on base (33.5/37.5ma)