*
* Copyright 2017 by iruchan, All rights reserved.
* 
* Generic pentode tube_model: Western Electric 403A, 408A, 6AK5
*
.SUBCKT 408A K G1 G2 A
BGG GG 0 V=V(G1,K)+ 0.62 
BEP EP 0 V=URAMP(V(A,K))+1e-10
BEG EG 0 V=URAMP(V(G1,K))+1e-10
BEG2 EG2 0 V=URAMP(V(G2,K))+1e-10
BM1 M1 0 V=( 1.63685946220193E-02 *(URAMP(V(EG2)-1e-10)+1e-10))**-0.852941176470588 
BM2 M2 0 V=( 0.6375 *(URAMP(V(GG)+V(EG2)/ 22.1460674157303 )+1e-10))** 2.35294117647059 
BP P 0 V= 3.42483781138136E-03 *(URAMP(V(GG)+V(EG2)/ 33.2191011235955 )+1e-10)**1.5
BIK IK 0 V=U(V(GG))*V(P)+(1-U(V(GG)))* 2.11603361960463E-03 *V(M1)*V(M2)
BIG IG 0 V= 1.71241890569068E-03 *V(EG)**1.5*(V(EG)/(V(EP)+V(EG))*1.2+0.4)
BIK2 IK2 0 V=V(IK,IG)*(1-0.4*(EXP(-V(EP)/V(EG2)*15)-EXP(-15)))
BIG2T IG2T 0 V=V(IK2)*( 0.82 *(1-V(EP)/(V(EP)+10))**1.5+ 0.18 )
BIK3 IK3 0 V=V(IK2)*(V(EP)+ 8500 )/(V(EG2)+ 8500 )
BIK4 IK4 0 V=V(IK3)-URAMP(V(IK3)-( 1.86822465128486E-03 *(V(EP)+URAMP(V(EG2,EP)))**1.5))
BIP IP 0 V=URAMP(V(IK4,IG2T)-URAMP(V(IK4,IG2T)-( 1.86822465128486E-03 *V(EP)**1.5)))
BIAK A K I=V(IP)+1e-10*V(A,K)
BIG2 G2 K I=URAMP(V(IK4,IP))
BIGK G1 K I=V(IG)
* CAPS
CGA G1 A 0.02p
CGK G1 K 1p
C12 G1 G2 0.025p
CAK A K 1p
.ENDS