• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

LTSpice models needed

Code:
* 6GK5_GE LTSpice model
* Modified Koren model (5 parameters) 0.541547mA
* Traced by Wayne Clay 12-21-2012 using Curve Captor v0.9.1
* from General Electric data sheet
.subckt 6GK5_GE  P G K
    Bp  P K  I=(0.1613820387m)*uramp(V(P,K)*ln(1.0+exp((2.74630225)+(2.74630225)*(110.0938181)*V(G,K)/sqrt((5.036113112k)+(V(P,K))**2)))/(2.74630225))**(1.055422106)
    Cgk G K 5.7p ; 0.7p added
    Cpk P K 3.7p ; 0.2p added
    Cgp G P 0.72p ; 0.2p added
    d3  G K dx1
.model dx1 d(is=1n rs=2k cjo=1pf N=1.5 tt=1n)
.ends 6GK5_GE
 
and this one... ;)
Code:
* 6GK5_GE-GP LTSpice model
* Koren model(5 parameters): mean fit error 0.249882mA
* Traced by Wayne Clay 12-21-2012 using Curve Captor v0.9.1
* from General Electric data sheet grid-plate transfer curves
.subckt 6GK5_GE-GP  P G K
    Bp  P K  I=(0.1452046509m)*uramp(V(P,K)*ln(1.0+exp((2.802767885)+(2.802767885)*(107.6098728)*V(G,K)/sqrt((5.497494886k)+(V(P,K))**2)))/(2.802767885))**(1.077094947)
    Cgk G K 5.7p ; 0.7p added
    Cpk P K 3.7p ; 0.2p added
    Cgp G P 0.72p ; 0.2p added
.ends 6GK5_GE-GP
 
EC88:
Code:
* ---------------------------------------------------------------------
* EC88 UHF triode LTSpice model
* Modified Koren model (8 parameters) mean fit error 0.199402mA
* Traced by Wayne Clay on 09/09/2007 using Curve Captor v0.9.1
* from La RadioTechnque data sheet
* ---------------------------------------------------------------------
.subckt EC88  P G K
    Bp  P K  I=(0.1461968258m)*uramp(V(P,K)*ln(1.0+(-0.1091553585)+exp
+ ((2.636947214)+(2.636947214)*((76.1162895)+(-3207.840539m)*V(G,K))*
+ V(G,K)/sqrt((62.88763962)**2+(V(P,K)-(26.31911466))**2)))/
+ (2.636947214))**(1.054580966)
    Cgp G P 2.4p ; 0.7p added
    Cgk G K 4.5p ; 0.7p added
    Cpk P K 0.255p ; 0.2p added

.ends EC88

If you have trouble with convergence with this model, try adding a reversed bias diode from grid to cathode.
 
Last edited:
Got this one from reVintage a while back.
Code:
.SUBCKT E180F 1 4 2 3
+ PARAMS: MU= 56.00 EX= 1.350 KG1= 250.0 KP=6709.19 KC= 850
+ KVB= 7.9 VCT= 0.00 RGI=2k
+ CCG=8.5P CPG1=0.03P CCP=3P
RE1 7 0 1G
RE2 8 3 1G
E1 7 0 VALUE= ; E1 BREAKS UP LONG EQUATION FOR G1.
+{V(4,3)/KP*LOG(1+EXP((1/MU+V(2,3)/V(4,3))*KP))}
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1*ATAN(V(1,3)/KVB)}
G2 8 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KC*(2.5708-ATAN(V(1,3)/KVB))}
E2 8 4 VALUE={0}
RCP 1 3 1G ; FOR CONVERGENCE
C1 2 3 {CCG} ; CATHODE-GRID 1
C2 1 2 {CPG1} ; GRID 1-PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
R1 2 5 {RGI} ; FOR GRID CURRENT
D3 5 3 DX ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS