(!!!) ECC83=12AX7 Philips Holland NOS 1966 (1.0/1.1ma and Gm=1600/1700)
(!!!!!) (Best RCA Pair 1968) 12AX7A RCA CMI gray ribbed plates NOS 1968 same date codes (best tone) (1.0/1.2ma and 1.0/1.3ma) 1-2% matched
(!!!!!) (Best Tungsram Pair) ECC83=12AX7 Tungsram Hungary NOS 1969 (1.1/1.2ma and 1.0/1.3ma) 1-3% matched
(!!!!!) (Best Value Single) 12AX7 IEC Mullard UK NOS 1965 copper grid posts (0.7/1.2ma and Gm=1400/1700)
(!!!!!) (Recommended Single) 12AX7 Mullard UK red tip mil-grade used/good 1965 copper grid posts (0.8/1.1ma and Gm=1400/1800) (163 series) (Fender, Marshall, Gibson)
(!!!!!) (slightly microphonic) 12AX7A RCA gray ribbed plates NOS 1970 era (1.1/2.3ma)
(!!!!!) (BEST PHONO PAIR) ECC83=12AX7 Siemens Halske Germany branded SONOTONE NOS 1962 (1.5/1.5ma and 1.4/1.5ma) 1-2% matched (Aesthetix, EAR, Lamm, VTL, Jadis, Nagra)
(!!!!) (Best GE Single) 12AX7A GE NOS 1967 (Gm=1550/1700) (1.2/1.4ma)
(!!!!) (Best Single) 12AX7 Raytheon Black Plates NOS 1962 faded printing (1.1/1.3ma and Gm=1500/1700)
(!!!!) (Best Single) 12AX7 Telefunken Germany smooth plates branded DYNACO like new 1965 (Gm=1600/1800)
(!!!!) (Best Single) 12AX7A Sylvania NOS 1960's (Gm=2100/2400 and 1.3ma/1.5ma)
(!!!!) (Best Single) 12AX7A Sylvania NOS 1960's (Gm=2600/3100 and 1.8ma/2.4ma)
(!!!!) (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 pair) 12AX7=ECC83 Telefunken Germany <> bottom ribbed plates used/good 1960 (0.7/0.9ma and 0.8/0.9ma)
(!!!!) (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 Raytheon Black Plates NOS 1962 slightly faded graphite coating on one plate - see photos (1.2/1.4ma and Gm=1700/1900)
(!!!!) (Best Value Single) 12AX7=ECC83 Mullard England ribbed plates NOS 1974 (163 Series) (0.8/1.0ma and Gm=1500/1650)
(!!!!) (Best Value Single) 12AX7=ECC83 Telefunken Germany <> bottom ribbed plates low hours/like new 1960 (Gm=1600/1800) (1.0/1.4ma)
