(!!!!!) (Recommended Single) ECC83=12AX7 Telefunken Germany smooth plates NOS 1963 (1.0/1.3ma and Gm=1500/1700)
(!!!!!) (Recommended Single) 12AX7 BRIMAR BVA England NOS narrow ribbed plates NOS 1960 (1.4/1.5ma) (Highest mA and Gm)
(!!!!) (Best Pair) CV4004=12AX7 Mullard UK box plates NOS 1971-1972 (1.1/1.2ma and 1.3/1.1ma)
(!!!!) (Best Value Single) 12AX7 Telefunken Germany smooth plates branded DYNACO like new 1964 (Gm=1600/1800 and 0.9/1.4ma)
(!!!!) (Best Tungsram Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1600/1700) (1.1/1.3ma)
(!!!!!) (Best Tungsram Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1900/1900) (1.2/1.5ma)
(!!!!) (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 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)
(!!!!) (Best Value Pair 1965 era) 12AX7=ECC83 Philips Miniwatt Holland like new 1964-1965 era (1.3/1.2ma and 1.1/1.2ma)
(!!!!!) (Best Pair 1963) 12AX7=ECC83 Mullard UK made for Knight like new ribbed plates 1963 (161 series) (1.0/1.0ma and 0.9/1.0ma) (1-3% matched)
(!!!!) (Slightly microphonic single) 12AX7=ECC83 Mullard UK branded Philips ribbed plates NOS 1962 (161 Series) (1.0/1.2ma and Gm=1600/1650)
(!!!!) (2nd Best Siemens Single) ECC83=12AX7 Siemens Halske NOS 1966 (1.0/1.1ma) (Gm=1550/1600)
(!!!!) (Recommended Pair) 12AX7=ECC83 Mullard England ribbed plates NOS 1966-1970 (163 Series) (1.1/1.0ma and 0.9/1.0ma)
(!!!) (Best Value Single) 12AX7=ECC83 FISHER HOLLAND large "O" getter halo 1960 used/good (Gm=1550/1600 and .9/1.0ma)
(!!!) (Best Value Single) 12AX7=ECC83 FISHER HOLLAND large "O" getter halo 1961 used/good (Gm=1500/1600 and .9/.9ma)
(!!!) (Recommended Single) 12AX7 RCA "tall gray plates" and "D" getter halo branded Raytheon used/good 1950's (Gm=1900/2100) (1.3/1.7ma)
(!!!) (Recommended Single 1962) ECC83=12AX7 Mullard Webcor ribbed plates used/very good 1962 (161 series) in white box (1.0/1.1ma and Gm=1600/1600)
(!!!) (Recommended Single) 12AX7A Sylvania NOS 1970's (Gm=2500/2800 and 2.2/2.7ma)