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Old 13th November 2013, 11:50 AM   #71
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I received an email from Ron Dekker yesterday indicating that the "manual" for the uTracer has been updated.

he's open to suggestions -- one of which I pass along -- allowing Vg2 to be a mathematical function of Vak -- for modeling ultralinear operation. Thus Vg2= k + 40% Vak where k is a constant.

i anxiously await V4 which should be able to test higher voltages and higher currents.
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Old 13th November 2013, 04:21 PM   #72
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I did not know that with Nick Barton's alternative UI, one could generate SPICE model directly with the uTracer until reading Kevin's post above, I think with some work, it could generate Ayumi's models as well. So I am too looking forward to the release of V4 of uTracer.
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Old 13th November 2013, 06:30 PM   #73
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Quote:
Originally Posted by jazbo8 View Post
Please take a look at Robert's post above. It gets very good results for pentodes and most tetrodes.
It look good for Hifi applications. Now, saturated guitar amplifiers have a functionment that is something in between class B and class C. That imply, when a tube is saturated, Ig1, Ig2, and the Ig2 on Ia interaction must be modelized. Before to find that paper with the model based on the constant current curves, I first try to start from the Koren model, and add parametrs to it. I get a model that was very complicated with a lot of parameters, and it was still necessary to add new parameters in order to get a better fit, mainly with the Ig2 on Ia interaction. So, I gave up with it. I also try to modify the Koren model by modelizing Ik and determine the other currents by substraction. It lokked very simple to start with, but at the end, this gave me the same complexity for a not better result. So I also gave ip with it.

Also, to draw a good SPICE model for the tetrod/pentod, to start from the constant current curves will simplify the model, because the internal tube parameters vary less for a given current than for a given voltage. It is also why I want to try it. The 807 have the same electrical caracteristics than a 6L6. The electrical differences between these 2 tubes are their limits. A 807 can handle 600 Ua and 300V Ug2, when most 6L6 will have big problems with more than 450-500 Ua. But for the SPICE model, LTspice or ng-spice will not explose and the same model can be used for both tubes.

So, it would be great to have a Robert's model for the 807 or 6L6. That in order to be able to compare it with the other models, inclusive the one I will made. But this is nothing urgent, because I am very busy, a lot of urgencies that must be solved, and I just don't have any time for development right now.

Last edited by Dominique_free; 13th November 2013 at 06:38 PM. Reason: typos
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Old 13th November 2013, 06:34 PM   #74
RajkoM is online now RajkoM  Bosnia and Herzegovina
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[QUOTE=

.model 5Y3 D(Is=1e-2 RS=180 Cjo=20p vj=2 N=400 bv=1400 mfg=Stephie type=vacuum )
.model 5R4 D(Is=1e-2 RS=150 Cjo=30p vj=2 N=305 bv=3100 mfg=Stephie type=vacuum )
.model 6X4 D(Is=1e-2 RS=121 Cjo=20p vj=2 N=256 bv=1250 mfg=Stephie type=vacuum )
.model 5U4 D(Is=1e-2 RS=103 Cjo=30p vj=2 N=250 bv=1550 mfg=Stephie type=vacuum )
.model 6AL5 D(Is=1e-2 RS=60 Cjo=5p vj=2 N=128 bv=330 mfg=Stephie type=vacuum )
.model 5AR4 D(Is=1e-2 RS=36 Cjo=30p vj=2 N=80 bv=1500 mfg=Stephie type=vacuum )
.model 0A2 D(Is=10u Rs=50 Cjo=10p nbv=147 bv=150 Ibv=20m Vpk=150 mfg=Stephie type=zener )
.model 0A3 D(Is=10u Rs=30 Cjo=10p nbv=72 bv=75 Ibv=20m Vpk=75 mfg=Stephie type=zener )
.model 0B2 D(Is=10u Rs=33 Cjo=10p nbv=105 bv=108 Ibv=20m Vpk=108 mfg=Stephie type=zener )
.model 5651 D(Is=1u Rs=1k Cjo=1p nbv=84 bv=85.5 Ibv=2.5m Vpk=85.5 mfg=Stephie type=zener )[/QUOTE]


In preamp just practically checked Mullard GZ30. Good spice model.

.model GZ30 D(Is=1e-2 RS=56 Cjo=30p vj=2 N=80 bv=1400 mfg=Mullard type=vacuum )
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Old 13th November 2013, 06:56 PM   #75
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Quote:
Originally Posted by Dominique_free View Post
So, it would be great to have a Robert's model for the 807 or 6L6. That in order to be able to compare it with the other models, inclusive the one I will made. But this is nothing urgent, because I am very busy, a lot of urgencies that must be solved, and I just don't have any time for development right now.
Robert's methodology only optimizes the plate characteristic so far, the screen characteristic is based on Koren's equation (which is still less than accurate). So you may want to look at Ayumi's 6L6 model to see if it meets your expectation. Below is his model for LTSpice:

Code:
*
* Generic pentode model: 6L6
* Copyright 2003--2008 by Ayumi Nakabayashi, All rights reserved.
* Version 3.10, Generated on Sat Mar  8 22:40:38 2008
*           Plate
*           | Screen Grid
*           | |  Control Grid
*           | |  |  Cathode
*           | |  |  |
.SUBCKT 6L6 A G2 G1 K
BGG   GG   0 V=V(G1,K)+0.91804059
BM1   M1   0 V=(0.10751078*(URAMP(V(G2,K))+1e-10))**-1.743575
BM2   M2   0 V=(0.4624527*(URAMP(V(GG)+URAMP(V(G2,K))/4.9999386)))**3.243575
BP    P    0 V=0.0016883841*(URAMP(V(GG)+URAMP(V(G2,K))/10.811784))**1.5
BIK   IK   0 V=U(V(GG))*V(P)+(1-U(V(GG)))*0.0021948901*V(M1)*V(M2)
BIG   IG   0 V=0.0022135943*URAMP(V(G1,K))**1.5*(URAMP(V(G1,K))/(URAMP(V(A,K))+URAMP(V(G1,K)))*1.2+0.4)
BIK2  IK2  0 V=V(IK,IG)*(1-0.4*(EXP(-URAMP(V(A,K))/URAMP(V(G2,K))*15)-EXP(-15)))
BIG2T IG2T 0 V=V(IK2)*(0.942171668*(1-URAMP(V(A,K))/(URAMP(V(A,K))+10))**1.5+0.057828332)
BIK3  IK3  0 V=V(IK2)*(URAMP(V(A,K))+2180)/(URAMP(V(G2,K))+2180)
BIK4  IK4  0 V=V(IK3)-URAMP(V(IK3)-(0.00056920996*(URAMP(V(A,K))+URAMP(URAMP(V(G2,K))-URAMP(V(A,K))))**1.5))
BIP   IP   0 V=URAMP(V(IK4,IG2T)-URAMP(V(IK4,IG2T)-(0.00056920996*URAMP(V(A,K))**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  0.6p
CGK   G1  K  5.7p
C12   G1  G2 3.8p
CAK   A   K  5.9p
.ENDS

Last edited by jazbo8; 13th November 2013 at 07:03 PM.
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Old 13th November 2013, 07:50 PM   #76
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Quote:
Originally Posted by jazbo8 View Post
Robert's methodology only optimizes the plate characteristic so far, the screen characteristic is based on Koren's equation (which is still less than accurate). So you may want to look at Ayumi's 6L6 model to see if it meets your expectation. Below is his model for LTSpice:
Thank you, I will test it when I get some time. Does he have a model for the EL84/6BQ5?
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Old 13th November 2013, 08:05 PM   #77
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Quote:
Originally Posted by Dominique_free View Post
Thank you, I will test it when I get some time. Does he have a model for the EL84/6BQ5?
No matter. I was looking in its website, but it was easier to search the forum instead. I downloaded the file from that post, and it have a lot of stufs, including the 6BQ5.
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Old 14th November 2013, 10:11 PM   #78
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Quote:
Originally Posted by Dominique_free View Post
So, it would be great to have a Robert's model for the 807 or 6L6. That in order to be able to compare it with the other models, inclusive the one I will made. But this is nothing urgent, because I am very busy, a lot of urgencies that must be solved, and I just don't have any time for development right now.
Dominique_free, I could probably put a 6L6/807 model together fairly quickly, but after modelling a number of different tubes, I've decided that I need to revise the "Frc" part of the model. The problem is that the curve fitting function veers off quite badly if you use grid voltages beyond the range over which it was fitted. Because of this, I don't want to be posting new tube model parameters when the underlying model may have to change.
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Old 18th November 2013, 09:58 PM   #79
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I was looking for 6ж52п spice models
Spice модели советских ламп для MICRO-CAP - Страница 4
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Old 24th November 2013, 02:13 AM   #80
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I'm a little puzzled with the quality of pentode models in spice. I used the uTracer to curve trace eight 6ж9п today and selected one that seemed to match the published curves reasonably well and generated a spice model from it using the alternate gui.

Testing in LTSpice confirmed that it did not match the measured curves closely at all. Extensive tweaking over the course of several hours got me something that looks plausible, but I don't trust it.

I subsequently used the trace from one of the tubes to generate a model using paint_kip, and was able to get a good match in the tool, but when I tested it in LTSpice again the results were not great, although much better than the untweaked model I generated using the uTracer.

Is it that these models just don't do a good job with high transconductance pentodes or as I now suspect with pentodes in general?

I did a quick sloppy trace using paint_kip and generated a model, I then added this model to my LTSpice tube library and tested it, as you can see they do not match at all. (See attachments)
Attached Images
File Type: png 6J9p-capture.png (150.3 KB, 323 views)
File Type: png 6j9p4-ltc trace.png (20.2 KB, 318 views)
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