(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)
6BC8 Westinghouse Canada NOS 1960's (6.0/6.6ma)
6BS8 Westinghouse NOS 1961 (9.8/10.2ma)
