(!!!!!) (2nd Best Pair 1962) ECC83=12AX7 Siemens Halske Germany branded SONOTONE NOS 1962 (1.1/1.1ma and 1.1/1.3ma) 1-2% matched (Aesthetix, EAR, Lamm, VTL, Jadis, Nagra)
(!!!!!) (2nd Best Siemens Pair 1968) CV492=ECC83=12AX7 Siemens Halske Germany NOS 1968 1-2% matched (1.2/1.3ma and 1.2/1.3ma) (best in phono stages and high end preamps)
(!!!!!) (3rd Best Siemens Pair 1968) CV492=ECC83=12AX7 Siemens Halske Germany NOS 1968 1% matched (1.1/1.1ma and 1.1/1.1ma) (best in phono stages and high end preamps)
(!!!!!) (3rd Best Siemens Pair 1968) CV492=ECC83=12AX7 Siemens Halske Germany NOS 1968 1-2% matched (1.1/1.1ma and 1.1/1.2ma) (best in phono stages and high end preamps)
(!!!!!) (Best Holland Pair 1967-1968) 12AX7=ECC83 Philips and Philips Miniwatt Holland ribbed plates "O" getter halo NOS 1967-1968 (1.3/1.5ma and 1.4/1.6ma) (close Gm)
(!!!!!) (Best Pair 1960-1961) 12AX7=ECC83 Philips Miniwatt Holland large getter halo "O" low hours/like new 1960-1961 (1.2/1.3ma and 1.2/1.1ma) 1-3% matched
(!!!!!) (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)
(!!!!!) (Best Pair 1974) 12AU7 Mullard UK NOS 1974 (10.5/10.7ma and 10.4/11.5ma) (Rogue, Hovland, Audio Note)
(!!!!!) (BEST PHONO PAIR) ECC83=12AX7 Siemens Halske Germany branded SONOTONE NOS 1962 (1.6/2.0ma and 1.6/1.7ma) 1-3% matched (Aesthetix, EAR, Lamm, VTL, Jadis, Nagra)
(!!!!!) (Best Siemens Pair 1972) E83CC=12AX7 Siemens Halske Germany NOS triple mica 1972 printed in 1976 (1.0/1.3ma and 1.1/1.3ma) (best in phono stages and high end preamps)
(!!!!!) (Best Single 1958) 12AX7=ECC83 Mullard UK "long plates" NOS 1958 (1.3/1.4ma)
(!!!!!) (Best Single 1963) CV492=12AX7 Mullard UK NOS 1963 (161 series) (1.3/1.3ma) 1% section balance
(!!!!!) (Best Single 1965) 12AX7 Mullard Bell & Howell UK NOS 1965 (1.3/1.2ma and Gm=1700/1600)
(!!!!!) (Best Tungsram Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1900/1900) (1.2/1.5ma)
(!!!!!) (Best Tungsram Single) ECC83=12AX7A Tungsram Hungary branded RCA NOS 1970's (Gm=2000/2300) (1.7/1.8ma) (Highest mA and Gm)
(!!!!!) (Best Value Single) 12AX7=ECC83 Mullard UK like new 1973 (1.8/1.1mA and Gm=2000/1600)
(!!!!!) (Recommended Pair) 12AX7=ECC83 Mullard UK ribbed plates NOS 1970-1974 (1.2/1.3ma and 1.2/1.1ma) (same Gm)
(!!!!!) (Recommended Pair) JAN-CTL6SL7WGT Tungsol NOS brown base gray ribbed plates 1961-1965 (2.1/2.2ma and 2.1/2.3ma) (low noise - very smooth sound) (phono grade)
(!!!!!) (Recommended Single) ECC83=12AX7 Telefunken Germany smooth plates NOS 1963 (1.0/1.3ma and Gm=1500/1700)
(!!!!!) (Recommended Single) ECC83=12AX7 Telefunken Germany smooth plates NOS 1972 (1.3/1.3ma and Gm=1700/1700) 1% section balance