I'm not new to electronics, but I am relatively new to SPICE
simulations. I've been looking around for a 12AV7 model to use with
Circuitmaker, but cannot find any. I know I could probably alter an
existing model to fit, but I wouldn't know where to begin; the
language of the models is Greek to me. Can anyone help?

Thanks.

You could try 5965, though it's not exactly the same. I once did a 5965
shootout and I rather liked the 12AV7 - I can see why you might be interested
in this much overlooked valve.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

"NewYorkDave" wrote

I'm not new to electronics, but I am relatively new to SPICE
simulations. I've been looking around for a 12AV7 model to use
with
Circuitmaker, but cannot find any. I know I could probably alter
an
existing model to fit, but I wouldn't know where to begin; the
language of the models is Greek to me. Can anyone help?

Firstly, most explanatory literature on spice is in PSpice. The two
most useful names to look up are Norman Koren and Duncan Munro. Both
have produced models and both explain their work on their sites.

http://www.duncanamps.com/

http://www.normankoren.com/Audio/

Secondly, you need to be able to translate from PSpice to 3f4.
Possibly best way is to look at one of Duncan's older models for
which both versions are available. Then the one should be a
translation of the other. Note that all the parameter passing stuff
in PSpice is incompatible with 3f4. The most important part you need
to understand is which variable is which, so you can change them
intelligently. Incidentally, the language is primitive rather than
complicated so you should be able to follow it quite soon...although
I still have difficulty with the 3f4 way of suppressing non-positive
values.

Thirdly, you need as comprehensive a set of characteristic curves
for your 12AV7 as you can get.

Fourthly, you set up a circuit and graphs in circuitmaker to produce
a set of curves for a valve you already have a model for, preferably
as close as possible to the one you want to model.

Fifthly you manually change the values in the model until your
curves are a close match to the published ones.

Finally you post your finished model to us!

cheers, Ian

NewYorkDave wrote:

I'm not new to electronics, but I am relatively new to SPICE
simulations. I've been looking around for a 12AV7 model to use with
Circuitmaker, but cannot find any. I know I could probably alter an
existing model to fit, but I wouldn't know where to begin; the
language of the models is Greek to me. Can anyone help?


I've hacked models of tubes before, I just play with
the various parameters to get the curves to
match what's in the data sheets. I can't claim to
understand what I'm doing though.... :-)

Give me a few days and I should be able to
hack up a model.

Other models I hacked up are he
http://home.netcom.com/~wb2jia/tubes/spice.txt

And others I found on the 'net:
http://home.netcom.com/~wb2jia/tubes/spice2.txt

Thanks, Andy. I've used the 12AV7 in some recent breadboarded designs
and I quite like it; it's kind of like a pumped-up 12AU7. I hope it
stays cheap and plentiful for a while.

I prefer actual breadboarding to simulation, but I do like to mess
around with ideas in Circuitmaker when I'm at my job and don't have
access to "the real thing."

NewYorkDave wrote:

I'm not new to electronics, but I am relatively new to SPICE
simulations. I've been looking around for a 12AV7 model to use with
Circuitmaker, but cannot find any. I know I could probably alter an
existing model to fit, but I wouldn't know where to begin; the
language of the models is Greek to me. Can anyone help?

Thanks.


I hacked this together, looks close:

*Vacuum Tube Triode (Audio freq.) pkg:VT-9 (A:1,2,3)(B:6,7,8)
..SUBCKT X12Av7A 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)--0.5

BRP1 RP1 0 V=URAMP(-V(GG)* 0.09869 )

BRP2 RP2 0 V=V(RP1)-URAMP(V(RP1)-0.999)

BRPF RP 0 V=(1-V(RP2)^ 1 )+URAMP(V(GG))* 0.1

BGR GR 0 V=URAMP(V(GG))-URAMP(-(V(GG)*(1+V(GG)* 0.012937 )))

BEM EM 0 V=URAMP(V(A)-V(K)+V(GR)* 25.093 )

BEP EP 0 V=(V(EM)^ 1.4 )*V(RP)* 0.00001863

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)--0.5 )^1.5)* 0.00012

BG G K I=V(GF)+V(LD)

* CAPS

CAK A K 0.00000000000024

CGK G K 0.00000000000323

CGA G A 0.0000000000019

..ENDS X12Av7A

Thanks for the replies, everybody. I appreciate the help.

Robert, thank you very much! I tried your model in some circuits I've
breadboarded in real life, and the performance is indeed very close to
how the real circuits behaved.

Now I just need to find (or learn how to make) some good 12AY7 and
12BH7 models and I'll be set for all the triodes I use regularly. I'm
already using Duncan's models for all the other common small-signal
triodes.

NewYorkDave wrote:
Robert, thank you very much! I tried your model in some circuits I've
breadboarded in real life, and the performance is indeed very close to
how the real circuits behaved.

Now I just need to find (or learn how to make) some good 12AY7 and
12BH7 models and I'll be set for all the triodes I use regularly. I'm
already using Duncan's models for all the other common small-signal
triodes.

Here's a 12BH7 model I got from somewheres off the 'net:

*. 12BH7, model based on EUVM type 311
..SUBCKT X12BH7 a g k
Bout ap k i = ((uramp((v(ap, k)/17.7212)+v(g, k)))^1.5)/515.571
Cgk g k 3.2e-12
Cga g a 2.6e-12
Cak a k 0.5e-12
Rleak g gp 10e+3
D1 a ap dx
D2 k ap dx2
D3 pg k dx
..model dx D(is=1.0e-12 rs=1.0)
..model dx2 D(is=1.0e-9 rs=1.0)
..ends X12BH7

NewYorkDave wrote:

Robert, thank you very much! I tried your model in some circuits I've
breadboarded in real life, and the performance is indeed very close to
how the real circuits behaved.

Thanks.

Now I just need to find (or learn how to make) some good 12AY7 and
12BH7 models and I'll be set for all the triodes I use regularly. I'm
already using Duncan's models for all the other common small-signal
triodes.

If you have any 12AZ7's, this model of the 12AC10 triode
should be close, as their specs are nearly identical:

*Vacuum Tube Triode
..SUBCKT X12AC10 A G K

* ANODE MODEL

BLIM LI 0 V=(URAMP((V(A)-V(K))))* 0.0037
BGG GG 0 V=((V(G)-V(K))*1.05)--0.5
BRP1 RP1 0 V=URAMP(-V(GG)* 0.09869 )
BRP2 RP2 0 V=V(RP1)-URAMP(V(RP1)-0.999)
BRPF RP 0 V=(1-V(RP2)^ 1 )+URAMP(V(GG))* 0.1
BGR GR 0 V=URAMP(V(GG))-URAMP(-(V(GG)*(1+V(GG)* 0.012937 )))
BEM EM 0 V=URAMP(V(A)-V(K)+V(GR)* 47.093 )
BEP EP 0 V=(V(EM)^ 1.43 )*V(RP)* 0.00000863
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)--0.5 )^1.5)* 0.00012
BG G K I=V(GF)+V(LD)

* CAPS

CAK A K 0.00000000000036
CGK G K 0.0000000000025
CGA G A 0.0000000000012

..ENDS X12AC10

NewYorkDave wrote:
Robert, thank you very much! I tried your model in some circuits I've
breadboarded in real life, and the performance is indeed very close to
how the real circuits behaved.

Thanks, but I think I improved the 12AV7 model, and made a 12AY7
model, both below

*************************************

*Vacuum Tube Triode (Audio freq.) pkg:VT-9 (A:1,2,3)(B:6,7,8)
..SUBCKT X12Av7A 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)--0.5
*below is variation of grid slopes
BRP1 RP1 0 V=URAMP(-V(GG)* 0.07069 )

BRP2 RP2 0 V=V(RP1)-URAMP(V(RP1)-0.999)

BRPF RP 0 V=(1-V(RP2)^ 1 )+URAMP(V(GG))* 0.1

BGR GR 0 V=URAMP(V(GG))-URAMP(-(V(GG)*(1+V(GG)* 0.012937 )))

BEM EM 0 V=URAMP(V(A)-V(K)+V(GR)* 28.093 )

BEP EP 0 V=(V(EM)^ 1.4 )*V(RP)* 0.00001963

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)--0.5 )^1.5)* 0.00012

BG G K I=V(GF)+V(LD)

* CAPS

CAK A K 0.00000000000024

CGK G K 0.00000000000323

CGA G A 0.0000000000019

..ENDS X12Av7A

***********************************

*Vacuum Tube Triode (Audio freq.) pkg:VT-9 (A:1,2,3)(B:6,7,8)
..SUBCKT X12Ay7A 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)--0.5
*below is variation of grid slopes
BRP1 RP1 0 V=URAMP(-V(GG)* 0.009869 )

BRP2 RP2 0 V=V(RP1)-URAMP(V(RP1)-0.999)

BRPF RP 0 V=(1-V(RP2)^ 1 )+URAMP(V(GG))* 0.1

BGR GR 0 V=URAMP(V(GG))-URAMP(-(V(GG)*(1+V(GG)* 0.012937 )))
*below is grid sensitivity
BEM EM 0 V=URAMP(V(A)-V(K)+V(GR)* 45.093 )
*below ^is grid linearity,*plate current at 0Vg
BEP EP 0 V=(V(EM)^ 1.3 )*V(RP)* 0.000007503

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)--0.5 )^1.5)* 0.00012

BG G K I=V(GF)+V(LD)

* CAPS

CAK A K 0.0000000000006

CGK G K 0.0000000000013

CGA G A 0.0000000000013

..ENDS X12Ay7A

************************************************** ******

Thanks, Robert! You've just made my lunchtime Circuitmaker experiments
much more enjoyable--and accurate! The updated 12AV7 model is working
even closer to what I measured in real life in my example circuits. And
I look forward to using the 12AY7 model.

As for the 12BH7 model: I've been using that same model you found on
the web, but it doesn't seem to reproduce the overload behavior of the
tube in actual circuits I've built. Obviously, that model doesn't
contain the level of detail that yours do.

wrote:
Thanks, Robert! You've just made my lunchtime Circuitmaker experiments
much more enjoyable--and accurate! The updated 12AV7 model is working
even closer to what I measured in real life in my example circuits. And
I look forward to using the 12AY7 model.

As for the 12BH7 model: I've been using that same model you found on
the web, but it doesn't seem to reproduce the overload behavior of the
tube in actual circuits I've built. Obviously, that model doesn't
contain the level of detail that yours do.

Thanks, but realize that I've only been changing a few
numbers (trial and error) to match the published
curves. As for "overload" do you mean when the signal
on the grid is too big, causing the tube to cut off
(and the non linear region just before cutoff), or
if you use too high plate currents or voltages?
I haven't tried to modify any parameters for excessive
currents or voltages on the plate.

That simpler model (12BH7) doesn't seem to create
the variation of slopes the 12AV7 model does.

Robert, thanks a lot! I look forward to using that 12AY7 model. And
your update of the 12AV7 model seems to be even closer to the real
thing, at least according to the circuits I'm simulating.

As for 12BH7: I've been using that same model you just posted, but it
doesn't work nearly as well as your models (probably becase it doesn't
contain the same level of detail). For instance, in a White cathode
follower circuit of mine, Circuitmaker is showing the ability to swing
+/-120V (peak) or more into 2400 ohms, while the real circuit can only
do +/-47V (peak) maximum into the same load before clipping.

Whoops... Sorry for responding twice. Google Groups just went to a
beta of a new version, and it crashed as I was trying to respond the
first time, so I thought my response hadn't gone through.