(!!!) (Recommended Single) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (54/40 and 55/40)
(!!!) (Recommended Single) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (54/40 and 56/40)
(!!!) (Recommended Single) JTL-6X4W Tungsol NOS 1955 curved "D" getter (48/40 and 50/40)
(!!!) (Recommended Single) JTL-6X4W Tungsol NOS 1955 curved "D" getter one section of internal plate bent at bottom (52/40 and 57/40)
(!!!) (Recommended Single) JTL-6X4WA Tungsol NOS 1962 curved "D" getter (55/40 and 60/40)
(!!!) (Single 1955) JG-12AY7 GE "D" getter like new 1955 (3.3/2.7ma) (High Gm)
(!!!) (Single 1956) 12AY7 GE "D" getter like new 1956 (3.1/2.8ma)
(!!!) (slightly microphonic) 5687 Tungsol black plates "U" getter halo branded GE NOS 1950's (36/40ma)
(!!!) 231=31 US Made Balloon NOS 1920's (14.2ma)
(!!!) 31 RCA Radiotron Balloon NOS 1920's (13.2ma)
(!!!) 35W4 RCA NOS 1970 era (52/40)
(!!!) 5881 Tungsol tests like new 1963 broken center guide pin (72.5ma)
(!!!) 5881 Tungsol used/good 1957 (58ma)
(!!!) 6336 Chatham metal plates used 1954 (59/74ma)
(!!!) 6336 Chatham metal plates used 1957 (57/53ma)
(!!!) 6EA7 Tungsol NOS 1960's (1.8ma/64ma) (strong single)
(!!!) 6V6GT Tungsol black plate coated glass used/good 1940's hairline crack in base (44ma)
(!!!) JAN-CTL-6AR6 Tungsol NOS 1951 gray oval plates (88ma)
(!!!) JTL-6X4W Tungsol NOS 1955 curved "D" getter halo (45/40 and 52/40)
(!!!) USN-CRC-1629=VT-138 RCA NOS 1940 (bright eye) (oldest single)
