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from unclejed613
6BF7 submini triode ("pencil" tube)
the 6BF7 is a dual triode with very similar characteristics to a 12AT7, except it's max plate voltage is 110V, and a little bit lower gain. this model is about 90% accurate, and is mostly a "ballpark" model. some tweaking of component values may be needed with a physical prototype.

.SUBCKT 6BF7 1 2 3 ; P G C; NEW MODEL
+ PARAMS: MU=35 EX=1.3 KG1=1180 KP=84 KVB=300 RGI=2000
+ CCG=2.3P CGP=2.2P CCP=1.0P ; ADD .7PF TO ADJACENT PINS; .5 TO OTHERS.
E1 7 0 VALUE=
+{V(1,3)/KP*LOG(1+EXP(KP*(1/MU+V(2,3)/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES IN MU-FOLLOWER
C1 2 3 {CCG} ; CATHODE-GRID; WAS 1.6P
C2 2 1 {CGP} ; GRID-PLATE; WAS 1.5P
C3 1 3 {CCP} ; CATHODE-PLATE; WAS 0.5P
D3 5 3 DX ; FOR GRID CURRENT
R1 2 5 {RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS


if anybody has a more accurate model, feel free to post it.