(slightly microphonic) 6BC8 Raytheon Japan branded Great Britain NOS 1970's (10.8/12.2ma) (High mA and Gm)
6BC8 Raytheon used/good 1962 no printing (5.6/7.8ma)
6BC8 Tungsol used/good "U" getter 1950's (5.4/6.8ma)
6BS8 RCA NOS 1966 (11.5/10ma)
6BS8 Tungsol NOS 1960 era (10.2/14ma)
