(!!!!!) (Best Pair 1950's) 7N7 Sylvania chrome top NOS 1956-1957 1-3% matched (8/9ma and 8.6/8.4ma) (best 6SN7 sub using adapter sockets)
(!!!!) (Best Pair #2) 7N7 Sylvania branded RCA and Sylvania NOS 1960-1963 (9.4/9.0ma and 9.6/9.8ma) (High Gm) 1-5% matched
(!!!!) (Best Pair #3) 7N7 Sylvania branded RCA 1960 era (8.4/8.4ma and 8.6/8.8ma) 1-3% matched
(!!!!) (Best Pair #3) 7N7 Sylvania branded RCA amd Sylvania 1960 era (8.4/9.5ma and 8.6/9.8ma) (same Gm) 1-3% matched
(!!!!) (BEST PAIR) 7C5 Sylvania branded International NOS 1960's (39ma and 40ma) (LOKTAL BASE 6V6GT)
(!!!!) (Best Pair) 7N7 Sylvania branded RCA 1960 era (10.4/10ma and 10.6/9.8ma) (High Gm) 1-3% matched (strong pair)
(!!!!) (Recommended Pair) 7N7 Sylvania branded GE chrome top NOS 1954-1956 (7.4/7.0ma and 7.4/7.2ma) 1-2% matched
(!!!) (BEST PAIR) 7AF7 Sylvania NOS gray round plates NOS 1950-1958 (8.5/8.7ma and 9.2/9.2ma) 1-5% matched (same Gm)
(!!!) (Recommended Pair) 7N7 Sylvania NOS branded GE and RCA 1960-1965 (9.4/8.0ma and 8.0/8.4ma) (close Gm)
(!!) (Best Single) 7AF7 Sylvania branded Hytron NOS round black plates NOS 1952 (9.6/9.4ma) 1-3% section balance
(!!) (Best Single) 7N7 Sylvania branded Philco NOS parallel black plates 1940's (7.5/7.9ma)
(!!) (PAIR) 7AF7 Sylvania branded RCA and GE NOS black round plates NOS 1956-1958 (7.0/7.6ma and 8.2/7.8ma) (close Gm matching)
(!!) 7N7 Sylvania branded Philco used/good short bottle parallel gray plates 1948 (7.2/7.6ma)
(!!) 7N7 Sylvania NOS 1960's (8.6/10.2ma)
(!) (BEST PRICE) 7E5=1201 US Brands NOS (4 tubes for $14.99)
(!) (Best Single) 7N7 Sylvania NOS 1960 era (10.8/11.2ma)
(!) (Good Single) 7N7 Sylvania branded GE NOS 1961-1962 (7.5/8.3ma)
(!) (Recommended Single) 7F7 Sylvania rebranded JAN-CBRZ-7F7 round gray plates used/like new 1940's (2.9/3.2ma) (highest testing single)
(!) (SINGLE) 7N7 Sylvania TALL BOTTLE branded Hytron parallel black plates chrome top NOS 1952 - small chip/blemish at top of tube (7.6/7.8ma)
(BEST PRICE) 7A5 NOS (4 for $11.99)