PSpice/LTSpice model for 12AY7/6072 wanted

[docali]

Hi,

I am looking for a PSpice/LTSpice model for 12AY7/6072 tube.
Maybe someone can provide this information. Thank's!

 

[Robert McLean]

model for 12AY7

Try this.


*
* model for one half of 12AY7
*
* heater not included
* Data extracted 16 June 2005
* from ElectroHarmonix 6072A/12AY7EH tube
*
.SUBCKT 12AY7 A G K
+ PARAMS: EX=1.18296637295072 MU=41.7794590897682 KG1=1283.6566442837 KP=328.825557514402 KVB=2847.72219152647
+ Go=0.34371558686874 KG=0.000213922190232166 AG=0.874211243853364 BG=0
+ CCG=1.3P CGP=1.3P CCP=0.6P
E1 4 0 VALUE={V(A,K)/KP*LN(1+EXP(KP*(1/MU+(V(G,K)-Go)/SQRT(KVB+V(A,K)*V(A,K)))))}
G1 A K VALUE={ (PWR(V(4),EX)+PWRS(V(4), EX))/(KG1) }
RCP A K 1G
G2 G K VALUE = {IF(V(G,K)>0,{Kg}*((({Ag}+V(A,K))/({Bg}+V(A,K)))**4)*V(G,K)**1.5,0)}
C1 G K {CCG} ; CATHODE GRID
C2 G A {CGP} ; GRID-PLATE
C3 A K {CCP} ; CATHODE-PLATE
.ENDS 12AY7

 

[docali]

Hi Robert,
thank you very much! The model works good compared to the old data sheets from RCA and GE showing only minor differences in curve behaviour. Unfortunately, I could not find the Electro Harmonix data sheet.

 

[Robert McLean]

EH 12AY7 data

docali :
I do not have an EH data sheet either. The data I used is measured from an actual tube. Just so you have something to compare to, here is the data I measured.

Vg Vp Ip (mA)
0 23.11 0.67
0 77.8 2.7
0 88.3 3.19
0 118.3 4.65
0 148.3 6.24
0 167.6 7.33
0 187.9 8.55
-0.5 39.6 0.56
-0.5 85.1 2.15
-0.5 121.1 3.76
-0.5 156.9 5.56
-0.5 182.1 6.96
-0.5 202.8 8.21
-1 38.46 0.14
-1 88.8 1.48
-1 116.3 2.59
-1 147.5 4.02
-1 178.1 5.6
-1 202.5 6.98
-2 81.3 0.22
-2 115.9 1.04
-2 144.7 2.1
-2 166.8 3.3
-2 200.7 4.66
-2 232.2 6.33
-5 164.6 0.05
-5 203.4 0.4
-5 248 1.49
-5 301.2 3.59
-6 262.6 0.84
-6 299.1 1.91

for +ve grid voltages
Vg Vp Ip (mA)
2 76 6.16
2 107.9 8.04
1 67.2 3.85
1 151.4 8.58
0.5 68 3.06
0.5 114.1 5.39
0.5 158.8 7.94

+ve grid voltages, this time measuring grid current
Vg Vp Ig (mA)
2 25.43 0.645
2 110.6 0.601
2 133.2 0.606
1 14.49 0.322
1 41.2 0.290
1 118.7 0.287
1 158.6 0.283

Sorry, but I cant seem to format this so the data lines up in columns correctly. Perhaps others may have some hints ?

 

[docali]

Very helpful information, Robert!

Thank you for your effort!

What mathematical method did you use to generate the model file?

 

[Robert McLean]

docali :
I use Koren's equations for plate current ( the E1 and G1 lines in the model ) and Rydel's equation for grid current ( the G2 line in the model ). I have an Excel spreadsheet in which I have entered these equations. I use Excels 'Solver' function to select values for the model parameters that result in the best fit of the model to the data. I have macros that generate plots of mu, rp, and gm vs current. This gives a good check of the resulting model and is easier to do in the spread sheet than in Spice, at least in my opinion.

If you search on the web you will find information on using Matlab for this, also there is a thread on this forum about revised Koren models and some software for deriving model parameters.

So there are lots of ways of doing it, I like my spreadsheets because they are mine and I can revise them as I see fit.