12AT7 Siemens Halske Germany D getter NOS 1957 (6ma/8ma)
12AT7=E81CC=6201 Siemens triple mica NOS 1971 (12/15.8ma)
12AT7WA Raytheon black plates - triple mica - O getter halo 1960's mis-matched triode sections (7/12ma)
12AT7WA=6201 GE NOS gray plates 1965 (7.8ma/10.6ma)
12DT8 RCA black plates NOS 1970 (23.0/24.4ma) (highest Ma and Gm)
12DT8 RCA gray plates NOS 1970's (12.2/16.4ma)
12DT8 RCA gray plates NOS 1970's (12.6/14.0ma)
6201=12AT7 GE "5 STAR" used/good triple mica "U" getter halo, copper grid posts, gray plates, 1957 (6.2/7.8ma)
6201=12AT7WA RCA Black Plates "o" getter halo used/like new 1961 (8.6/7.8ma)
6679 (see 12AT7)
