(!!!!) (Recommended GE Pair) 5U4GB GE NOS 1968 same date codes (58-60/40 and 58-60/40)
(!!!!) (Recommended Pair) 5U4GB RCA NOS and like new 1962 (56-58/40 and 56-58/40)
(!!!!) (Recommended Pair) 6CA4 RFT East Germany (Funkwerk) NOS 1970's (48-48/40 and 49-49/40)
(!!!!) (Recommended Pair) 6CA4 RFT East Germany (Funkwerk) NOS 1970's (47-48/40 and 48-48/40)
(!!!!) (Recommended Pair) 6CA4 RFT East Germany (Funkwerk) NOS 1970's (49-49/40 and 48-49/40)
(!!!!) (Single) 6106 Bendix rebranded 5Y3WGTA Heintz & Kaufman NOS (63/40 and 64/40)
(!!!!) 5AS4A Raytheon "D" getter 1960 era (58/40 and 62/40) (uprated 5U4GB)
(!!!!) 5U4G GE NOS 1952 (55/40 and 51/40)
(!!!!) UX-280 RCA Radiotron Balloon used/60% 1930 era some white oxide flakes inside tube (38/40 and 38/40)
(!!!) (BEST PAIR) 12AL5 Tungsol NOS 1960 (48-48/40 and 48-48/40)
(!!!) (Best Pair) 5Z4 RCA NOS 1959 (50-50/40 and 51-51/40)
(!!!) (Best Pair) 5Z4 RCA NOS 1959 (51-51/40 and 52-52/40)
(!!!) (Best Pair) 6663=6AL5 Tungsol NOS 1950's (48-48/40 and 48-49/40)
(!!!) (BEST PAIR) 6AL5 GE branded RCA NOS 1970's (48-48/40 and 47-48/40)
(!!!) (BEST PAIR) 6AL5 RCA NOS 1970 era (48-50/40 and 50-50/40)
(!!!) (BEST PAIR) 6AL5 RCA NOS 1970's (48-50/40 and 48-50/40)
(!!!) (Best Pair) JAN-CEA-5852=6X5GT Bendix NOS 1953 (63-64/40 x 2 sections) 1% matched (Best Audio Grade 6X5GT)
(!!!) (Best Price) 5726=6AL5 Sylvania JAN NOS (4 for $8.99)
(!!!) (BEST PRICE) 80 US Brands used/good (5 in stock) ($9.99 each)
(!!!) (BEST RCA SINGLE) 6CA4 RCA NOS 1963 (53/40 and 54/40)