improvement to DM's "generic" 12AU7 spice model

Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

By adjusting parameter values of Duncan Munro's "generic triode model" for the 12AU7, I was able to get it pretty close to the published plate curves. The base spice circuit before changes was WAY off. Like, not even close.
The AC performance seems pretty close, but it's showing only about half the distortion, and slightly less gain than the Sylvania tube manual. No idea why.
Has anybody else done better? Or can you suggest which parameter to change to get the high current zone closer? I'm basically blindly changing things right now.
Thanks!
Joel

***********************************
12AU7 Test Circuit
.dc Vb 0 500 1 Vc 0 30 2
Vb 2 0 250v
Vk 3 0 0
Vc 0 1 8
x1 2 1 3 12au7
.subckt 12au7 a g k
* ANODE MODEL
BLIM LI 0 V=(URAMP(V(A)-V(K))^1)*0.0037
BGG GG 0 V=V(G)-V(K)-0
BRP1 RP1 0 V=URAMP(-V(GG)*0.024778659)
BRP2 RP2 0 V=V(RP1)-URAMP(V(RP1)-0.999)
BRPF RP 0 V=(1-V(RP2)^.68)+URAMP(V(GG))*0.1
BGR GR 0 V=URAMP(V(GG))-URAMP(-(V(GG)*(1+V(GG)*0.007)))
BEM EM 0 V=URAMP(V(A)-V(K)+V(GR)*16)
BEP EP 0 V=(V(EM)^1.35)*V(RP)*0.0000236
BEL1 EL1 0 V=URAMP(V(EP))
BEL EL 0 V=V(EL1)-URAMP(V(EL1)-V(LI))
BLD LD 0 V=URAMP(V(EP)-V(LI))
BAK A K I=V(EL)
* GRID MODEL
BGF GF 0 V=(URAMP(V(G)-V(K)-0)^1.5)*0.01
BG G K I=V(GF)+V(LD)
* CAPS
Cak a k 0.4pF
Cgk g k 1.6pF
Cga g a 1.5pF
.ends 12au7
.control
.endc
.probe
.end

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Topic - improvement to DM's "generic" 12AU7 spice model - Joel Tunnah 07:40:42 01/27/06 (0)

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