(!!!!!) (Best Overall Single) ECC83=12AX7 Telefunken Germany smooth plates NOS 1965 (1.3/1.5ma and Gm=1800/2000) (Highest mA and Gm)
(!!!!) (Best Value Single) 12AX7 Telefunken Germany <> bottom smooth plates branded GAP/R Computor tube like new 1964 (Gm=1700/1600 and 1.1/1.0ma)
(!!!!) (Best Value Single) 12AX7 Telefunken Germany <> bottom smooth plates branded GAP/R Computor tube like new 1964 (Gm=1700/2000 and 1.1/1.5ma)
(!!!!) (Best Value Single) 12AX7 Telefunken Germany smooth plates branded DYNACO like new 1964 (Gm=1600/1800 and 0.9/1.4ma)
(!!!!) (Recommended Pair) 7199 RCA black plates NOS 1960's (12/6.6ma and 13.2/7.0ma)
(!!!!) (Recommended Single) 7199 RCA black plates NOS 1960's (19.5ma pentode / 8ma triode)
(!!!) (Best Pair) 7199 RCA Black Plates NOS 1960's (14/7.2ma and 14/8.2ma)
(!!!) (Single) 7199 RCA Black Plates NOS 1964 (10.2ma pentode, 12ma triode)
(!!!) (Single) 7199 RCA Black Plates NOS 1970 era (10.6/8.6ma)
(!!) (2nd Best Pair) 7199 Sylvania NOS 1960's and 1985 same build (12.5ma/9.6ma and 12.3/10.2ma) 1-3% matched
(!!) (Best Value Single) 7199 Sylvania branded GE NOS 1966 (10ma/8.6ma)
(!!) (Best Value SIngle) 7199 Sylvania NOS 1970 (15ma pentode/6.2ma triode)
(!!) (Good Value Single) 7199 Sylvania like new 1962 (11ma pentode, 8.5ma triode)
(!!) (Single) 7199 Sylvania NOS 1960's (11.8ma pentode, 7.8ma triode)
(!!) 7199 RCA Black Plates NOS around 1960 era (9/7.8ma)
12X4 GE GM Delco gray plates "D" getter NOS 1960 era (49/40 and 50/40)
12X4 GE gray plates "D" getter NOS 1960 (50/40 and 50/40)
12X4 RCA black plates "D" getter NOS 1950's faded printing (49/40 and 50/40)
12X4 RCA black plates "D" getter NOS 1956 (49/40 and 50/40)
12X4 Tungsol branded Raytheon black plates "D" getter NOS 1960 era (44/40 and 44/40)
