(!!!!) (Best Value Pair) 12AX7 Telefunken Germany <> bottom ribbed plates used/very good 1960 era (1.0/1.2ma and 1.0/1.1ma) 1-5% matched
(!!!!) (Best Value Pair) 12AX7=ECC83 Philips Miniwatt Holland tests like new 1963-1965 era (1.1/1.1ma and 1.1/1.1ma) 1-3% matched
(!!!!) (Best Value Pair) 12AX7=ECC83 Telefunken Germany <> bottom smooth plates used/good 1960's (0.8/0.8ma and 0.8/1.0ma)
(!!!!) (Best Value Single) 12AX7 Hitachi Japan branded ITT NOS 1963 (1.0/1.7ma and Gm=1500/1950)
(!!!!) (Best Value Single) 12AX7 Raytheon Black Plates NOS 1962 (.9/1.1ma and Gm=1400/1600)
(!!!!) (Best Value Single) 12AX7 Telefunken Germany smooth plates branded DYNACO like new 1964 (Gm=1600/1800 and 0.9/1.4ma)
(!!!!) (Best Value Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1500/1600) (0.9/1.0ma)
(!!!!) (Best Value Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1500/1800) (0.9/1.2ma)
(!!!!) (Best Value used) ECC83=12AX7 Fisher Mullard ribbed plates used/good 1964 (.8/1.2mA Gm=1400/1600)
(!!!!) (Best Value used) ECC83=12AX7 Fisher Mullard ribbed plates used/good 1964 copper grid posts (.7/.8mA Gm=1400/1500)
(!!!!) (Good Value 1962) M8137=12AX7S Philips SQ France ribbed plates NOS 1962 (0.8/0.9ma and Gm=1350/1350) (Special Quality 12AX7)
(!!!!) (Good Value 1962) M8137=12AX7S Philips SQ France ribbed plates NOS 1962 (1.1/1.1ma and Gm=1550/1450) (Special Quality 12AX7)
(!!!!) (Good Value Single) JRP-12AX7 Raytheon Black Plates NOS 1962 (Gm=1300/1500) (0.7/1.0ma)
(!!!!) (Good Value Single) JRP-12AX7 Raytheon Black Plates NOS 1962 (Gm=1300/1600) (0.7/1.1ma)
(!!!!) (Good Value Single) JRP-12AX7 Raytheon Black Plates NOS 1962 (Gm=1500/1700) (0.9/1.2ma)
(!!!!) (Holland single 1958) ECC83=12AX7 Triotron Holland "long plates" with "D" getter halo like new 1957 (1.1/1.2ma and Gm=1700/1700)
(!!!!) (Recommended Pair) 12AX7 Philips and Valvo Holland NOS 1965-1966 era (1.2/1.1ma and 1.3/1.2ma)
(!!!!) (Recommended Pair) 12AX7=ECC83 Mullard England ribbed plates NOS 1966-1970 (163 Series) (1.1/1.0ma and 0.9/1.0ma)
(!!!!) (Recommended Pair) 12AX7=ECC83 Philips and Pope Holland NOS 1965-1967 (2.1/1.8ma and 1.6/2.1ma) (Highest mA and Gm)
(!!!!) (Recommended Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.5/1.6ma and 1.4/1.7ma)