(!!) 12AU7 Hitachi JAPAN branded IEC Mullard ribbed plates 1969 (12.8/13.4ma) (Same Gm)
(!) (slightly microphonic single) 12AU7 Hitachi JAPAN branded IEC Mullard NOS ribbed plates 1968 (9.4/11ma)
(!) 12AU7A Hitachi JAPAN branded Realistic Lifetime NOS ribbed plates 1960 era (9.2/12.2ma)
25L6GT Tungsol NOS 1950's (88/60)
25L6GT Tungsol NOS 1950's (89/60)
