(!!!!) (BEST SIEMENS PAIR) EL84 Siemens Halske Germany NOS 1969 (47.5ma and 50.4ma)
(!!!!) (Best Siemens Pair) EL84 Siemens Halske Germany used/test like new 1971 (48.2ma and 48.5ma) (High Gm)
(!!!!) (Best Siemens Single) ECC83=12AX7 Siemens Halske Germany branded SONOTONE NOS 1960 (Gm=1900/2200) (1.3/1.7ma)
(!!!!) (Best Siemens Single) ECC83=12AX7 Siemens Halske Germany branded SONOTONE NOS 1962 (Gm=1900/1700) (1.5/1.3ma)
(!!!) (Best Single) ECC83=12AX7 Siemens Halske Germany NOS 1966 (162 Series) (Gm=1500/1600 and 1.0/1.1ma)
(!!!) (Best Value Single) 12AX7=ECC83 SIEMENS HALSKE GERMANY used/good 1966 (0.8/0.9ma)
(!!!) (Best Value Single) 12AX7=ECC83 SIEMENS HALSKE GERMANY used/good 1967 (0.8/0.9ma)
(!!!) (Best Value Single) ECC83=12AX7 Siemens Halske Germany used/good 1960's faded date code (1.3/0.9ma and Gm=1700/1500)
(!!!) (Recommended Single) 12AX7WA=E83CC SIEMENS HALSKE GERMANY triple mica used/tests like new 1969 (1.2/1.0ma)
(!!) (Good Value) 12AX7 Siemens Halske Germany rebranded "BOGEN" used/good 1960 (161 Series) (Gm=1400/1500 and 0.8/0.9ma)
