(!!) (Recommended Single) 6350 Sylvania black plate NOS "U" getter halo 1957 (9/10ma)
(!!) 12AT7 Brimar England black plates "U" getter used/good 1950's (6.0/6.4ma)
(!!) 5814A RCA black plates used/good 1964 (7.2/8.4ma)
(!!) 6350 RCA NOS triple mica "U" getter NOS 1960 era (12.8/13.2ma)
(!!) 6350 Sylvania black plates rebranded United "U" getter used/good 1950's (8.7/9.3ma)
(!!) 7025 CBS used/good "U" getter halo 1960 era (Gm=1400/1300 and 0.7/0.7ma)
(!!) JG-5814A GE NOS 1965 (9/10ma)
(!) (Slightly microphonic) JG-5814A GE NOS triple mica "U" getter halo 1956 (10.2/10.4ma) 1-2% section balance (high Ma and Gm)
(!) 12AU7 Tungsol gray ribbed plates NOS square or "D" getter halo 1954 in white box (8.2/8.6ma)
(!) JTL-12AU7 Tungsol narrow plates "D" getter NOS 1955 bottom mica is tilted (10.4/10.6ma)
(slightly microphonic) 12BH7 GE Zenith NOS "U" getter 1953 (10.0/10.6ma)
(sold out) 6414 Raytheon triple mica black plates NOS 1950's misbranded E80CC National
6CG7 Sylvania Emerson used/good chrome electrostatic shield between plates "U" getter 1957 (6.2/6.8ma)