(!!!) (Recommended Pair) JTL-5654=6AK5W Tungsol gray plate "D" getter used/good 1956-1958 (6.4ma and 6.5ma)
(!!!) (Recommended Single) 6SN7GTB Sylvania chrome top gray plates low hours 1950's (8.6ma/8.4ma)
(!!!) (Recommended Single) 6SN7GTB Sylvania NOS 1960's (7.2ma and 6.6ma)
(!!!) (Recommended Single) 6SN7GTB Sylvania used/tests like new 1960's (8.2ma and 7.6ma)
(!!!) (Single) JG-5670WA GE triple mica with D getter NOS 1956 (5.5/5.8ma) (same Gm)
(!!!) 12BH7 GE Silvertone gray oval plates NOS "U" getter 1953 (8.2/8.0ma)
(!!!) 12BH7A GE NOS gray oval plates 1960's (9.5/13.5ma)
(!!!) 5881 Tungsol used/good 1957 (58ma)
(!!!) 6SN7GTA Sylvania "chrome top" TALL bottle used/good 1950 era (6.2/6.2ma)
(!!) (#1 12AU7 Raytheon from 1954) 12AU7 Raytheon gray ribbed plates "D" getter halo NOS 1954 (10.6/11.2ma)
(!!) (#1 12AU7 Raytheon from 1956) 12AU7 Raytheon gray ribbed plates super large "U" getter halo NOS 1956 (10.4/10.8ma) (High Ma and Gm)
(!!) (#1 12AU7A Raytheon 1960's single) 12AU7A Raytheon Uniline gray ribbed plates "O" getter NOS 1960's (8.2/11ma)
(!!) (#1 5687 Tungsol used 1950's) 5687 Tungsol rebranded IBM bronze plates "U" getter used/very good late 1950's (32.5/39ma)
(!!) (#1 5687 Tungsol used 1961) 5687WA Tungsol bronze plates "O" getter halo used/very good 1961 (33.4/34.8ma)
(!!) (BEST VALUE) 12AY7 GE branded Raytheon NOS "O" getter 1960's (2.6/2.3ma)
(!!) (single) 6SL7GT RCA NOS black plates gray coated glass 1959 (2.0/1.7ma)
(!!) 6AN8A Sylvania coated glass NOS 1960's (20.2/11.2ma)
(!!) 6SN7GT Raytheon taller bottle parallel black plates NOS 1949 (8.2/8.0ma)
(!!) JRC-12AU7 RCA NOS long gray plates mid-1950's "D" getter (9/11.6ma)
(!!) JTL-5687WA Tungsol bronze plates "O" getter used/good 1958 (30/30.5ma)