(!!!) (Best Value Single) 12AX7=ECC83 SIEMENS HALSKE GERMANY like new 1966 (1.0/1.1ma)
(!!) (Best Single 1966) ECC83=12AX7 Siemens Halske Germany NOS 1966 (162 Series) (Gm=1500/1600 and 1.0/1.1ma)
(!!) (Good Value) 12AX7 Siemens Halske Germany rebranded "BOGEN" used/good 1960 (161 Series) (Gm=1400/1500 and 0.8/0.9ma)
(!) (Good Value) ECC83=12AX7 Siemens Halske Germany used/good 1960's in white box (Gm=1500/1700)
