(!!!!) (Best Holland Single) 12AX7A=ECC83 Amperex Globe Logo Holland ribbed plates NOS 1970 (1.4/1.4ma and Gm=1700/1800) 1-2% section balance
(!!!!) (Best Mullard Single) 12AU7A Amperex by Mullard UK NOS ribbed plates 1974 (10.6/11.6ma) (DAC, linestage)
(!!!!) (Best Single 1961) 12AX7=ECC83 Mullard UK ribbed plates NOS 1961 (161 Series) (1.1/1.1ma and Gm=1600/1700)
(!!!) (Recommended Single) EF94=6AU6 Tungsol used/tests like new 1957 (10ma)
