(!!!!!) (2nd Best Single 1958) 12AX7=ECC83 Mullard UK "long plates" NOS 1958 (1.3/1.4ma) (f91 series)
(!!!!!) (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 Holland Pair) 12AX7=ECC83 Philips Miniwatt Holland like new "O" getter halo 1961 (1.4/1.6ma and 1.4/1.5ma) (Highest mA and Gm) 1-2% matched
(!!!!!) (Best Mullard Pair) 12AX7=ECC83 Mullard UK ribbed plates NOS 1970-1974 (1.2/1.3ma and 1.2/1.1ma) (same Gm)
(!!!!!) (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 Pair) 12AX7=ECC83 Philips Holland like new 1968 same date codes (1.5/1.7ma and 1.7/1.8ma) (Highest mA and Gm) 1-3% matched
(!!!!!) (Good Value Single) 12AX7 BRIMAR BVA England narrow ribbed plates like new 1959 (1.0/1.2ma)
(!!!!!) (Recommended Single) 12AX7 BRIMAR BVA England NOS narrow ribbed plates NOS 1960 (1.4/1.5ma) (Highest mA and Gm)
(!!!!!) (Recommended Single) ECC83=12AX7A Tungsram Hungary branded RCA NOS 1970's (Gm=1700/1900) (1.0/1.4ma)
(!!!!) (Best Pair #2 - best value) 12AX7 Telefunken Germany <> bottom ribbed plates used/very good 1960 era (0.9/1.0ma and 1.0/1.1ma) 1-5% matched (close Gm)
(!!!!) (Best Pair) 12AX7 EI Yugoslavia Smooth Plates TELEFUNKEN copy NOS 1981 (1.1/1.1ma and 1.0/1.2ma) 1-5% matched
(!!!!) (Best Pair) 12AX7 GE branded 12AX7A International NOS 1977 (1.3/1.3mA and 1.4/1.4ma) (Same Gm) 1-2% matched
(!!!!) (Best Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.3/1.6ma and 1.4/1.6ma) 1-3% matched (high Gm)
(!!!!) (Best Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.4/1.4ma and 1.4/1.4ma) 1-2% matched
(!!!!) (Best Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.5/1.4ma and 1.5/1.4ma) 1% matched
(!!!!) (Best Siemens Single) CV492=ECC83=12AX7 Siemens Halske NOS 1968 (1.2/1.5ma) (Gm=1800/1900) (phono, mic, preamp)
(!!!!) (Best Single 1958) 12AX7 GE tall gray ribbed plates "U" getter 1958 like new (Gm=1800/1800 and 1.3/1.3ma) 1% section balance
(!!!!) (Best Single 1961) 12AX7=ECC83 Philips Miniwatt Holland 1961 large "O" getter halo NOS (1.8/1.3ma and Gm=2100/1700)
(!!!!) (Best Single) ECC83=12AX7 Telefunken Germany <> bottom smooth plates 1964 (1.3/1.5ma and Gm=1700/1800)
(!!!!) (Best Tungsram Single) ECC83=12AX7 Tungsram Hungary NOS 1982 (1.6/1.5mA and Gm=2100/2000) (high Ma and Gm)
