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24th November 2013, 04:49 AM  #81 
diyAudio Moderator

Kevin,
I have been struggling with this issue for sometime, while some may not agree, but I think the culprit lies in the Koren pentode model itself, which is used in both the alternate GUI (in uTracer) and Dmitry's Paint_kip. You can improve the results with Jack's custom Excel Solver routine or Robert's multiparameter pentode model (see his post above), but I found it is easier to use Ayumi's methodology, while not flawless (especially around the knees), it can get very good matches between the models and the datasheets. I will be making a translated version of Ayumi's article on SPICE model building available once I get my PC back, hopefully soon... or you can read the original article with Google Translate, and take a look at the equivalent circuit used for the model. 
24th November 2013, 11:38 AM  #82  
diyAudio Member
Join Date: Feb 2009

Quote:
I'm not familiar with 6Z9P, but E180F. They are very similar. First look ..... MU=84.8 is impossible. Create a model based on MU~55 or so. Your curves with uTracer are correct based on the datasheet. If you atach your uTracer curves for 6Z9P only, I will try to help. 

24th November 2013, 12:35 PM  #83 
diyAudio Member

I think I broke my uTracer. Probably just a matter of replacing the output switching transistors.
The pentode models work very well in ultralinear mode. Credit for the Excel model should go to Pierre Teouzelet who described it in AudioXpress a few years ago. If anyone wants a copy of the spreadsheet pm and send an email address. In the meanwhile, the pentode models will tell you whether the circuit is going to be stable. It's probably more useful to have an optimization model for the load line from which you can derive some approximation of THD% and power. 
24th November 2013, 09:05 PM  #84  
diyAudio Moderator

Quote:
Edit: Interestingly enough I retraced 6j9p4 and once again was not able to get a good fit with a mu under 80, testing in LTSpice revealed the same issue as shown in my earlier post. Changing the just mu in the model to 55 in LTSpice resulted in a good match. KG2 apparently has an effect on screen current which I am currently exploring. Sanity check anyone: After some tweaking the following model seems to match both expected plate currents and screen currents quite well for a screen voltage of 150V: **** 6J9P4 ****************************************** * Created on 11/24/2013 20:06 using paint_kit.jar 2.6 by Kevin Kennedy * www.dmitrynizh.com/tubeparams_image.htm * Plate Curves image file: 6J9P4.gif * Data source link: * Model parameters MU and KG2 tweaked to match model to * measured device params * .SUBCKT 6J9P4 1 4 2 3 ; P S G K + PARAMS: CCG=7.8P CGP=0.02P CCP=2.7P RGI=2000 + MU=55 KG1=387 KP=692 KVB=12 EX=1.71 KG2=750 * Vp_MAX=250 Ip_MAX=40 Vg_step=0.5 Vg_start=0.5 Vg_count=5 * RE1 7 0 1MEG ; DUMMY SO NODE 7 HAS 2 CONNECTIONS 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 4 3 VALUE={(EXP(EX*(LOG((V(4,3)/MU)+V(2,3)))))/KG2} RCP 1 3 1G ; FOR CONVERGENCE C1 2 3 {CCG} ; CATHODEGRID 1 C2 1 2 {CGP} ; GRID 1PLATE C3 1 3 {CCP} ; CATHODEPLATE 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
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"To argue with a person who has renounced the use of reason is like administering medicine to the dead."  Thomas Paine 

24th November 2013, 09:14 PM  #85  
diyAudio Moderator

Quote:
I'm using high transconductance pentodes in voltage amplifier circuits and would like to have a model that provides a somewhat accurate representation of gain. Large variations in transconductance (+/20% or more) are part and parcel of these types so I take the gain with a grain of salt, but when a model generated directly from the curves is not even close..
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"To argue with a person who has renounced the use of reason is like administering medicine to the dead."  Thomas Paine 

24th November 2013, 11:07 PM  #86 
diyAudio Member
Join Date: Feb 2009

Kevin,
this is mine, done quickly and could be finalized. Pay attention to the pinout P K G2 G1, due to a large IG2. For me it is: SUCKT 6J9P 1 2 3 4 P K G2 G1 Also, look capacitance values. This is complete model: **** 6J9P_4 ****************************************** * Created on 11/25/2013 00:58 using paint_kit.jar 2.6 * Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively * Plate Curves image file: 6j9p_4.jpg * Data source link: * .SUBCKT 6J9P**** 6J9P************************************* * Created on 11/25/2013 00:35 using paint_kit.jar 2.6 * Model by E74GD * Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively * Plate Curves image file: 6j9p_4.jpg * Data source link: * .SUBCKT 6J9P 1 4 2 3 ; P K G2 G1 + PARAMS: CCG=8.5P CGP=0.03P CCP=3P RGI=2000 + MU=55.9 KG1=280.9 KP=369.1 KVB=23.1 EX=1.49 KG2=1147.5 * Vp_MAX=480 Ip_MAX=40 Vg_step=0.5 Vg_start=0.5 Vg_count=5 * Rp=1600 Vg_ac=23.5 P_max=7.5 Vg_qui=23.4 Vp_qui=240 UL=0.469 EG2=139.2 * X_MIN=73 Y_MIN=50 X_SIZE=365 Y_SIZE=256 FSZ_X=1032 FSZ_Y=742 XYGrid=false * showLoadLine=n showIp=y isDHT=n isPP=n isAsymPP=n isUL=n showDissipLimit=n * showIg1=y gridLevel2=n isInputSnapped=n * XYProjections=n harmonicPlot=y harmonics=y * RE1 7 0 1MEG ; DUMMY SO NODE 7 HAS 2 CONNECTIONS 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 4 3 VALUE={(EXP(EX*(LOG((V(4,3)/MU)+V(2,3)))))/KG2} RCP 1 3 1G ; FOR CONVERGENCE C1 2 3 {CCG} ; CATHODEGRID 1 C2 1 2 {CGP} ; GRID 1PLATE C3 1 3 {CCP} ; CATHODEPLATE 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 *$ 1 2 3 4 ; P G K G2 + PARAMS: CCG=8.5P CGP=0.03P CCP=3P RGI=2000 + MU=55.9 KG1=280.9 KP=369.1 KVB=23.1 EX=1.49 KG2=1147.5 * Vp_MAX=480 Ip_MAX=40 Vg_step=0.5 Vg_start=0.5 Vg_count=5 * Rp=1600 Vg_ac=23.5 P_max=7.5 Vg_qui=23.4 Vp_qui=240 UL=0.469 EG2=139.2 * X_MIN=73 Y_MIN=50 X_SIZE=365 Y_SIZE=256 FSZ_X=1032 FSZ_Y=742 XYGrid=false * showLoadLine=n showIp=y isDHT=n isPP=n isAsymPP=n isUL=n showDissipLimit=n * showIg1=y gridLevel2=n isInputSnapped=n * XYProjections=n harmonicPlot=y harmonics=y * RE1 7 0 1MEG ; DUMMY SO NODE 7 HAS 2 CONNECTIONS 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 4 3 VALUE={(EXP(EX*(LOG((V(4,3)/MU)+V(2,3)))))/KG2} RCP 1 3 1G ; FOR CONVERGENCE C1 2 3 {CCG} ; CATHODEGRID 1 C2 1 2 {CGP} ; GRID 1PLATE C3 1 3 {CCP} ; CATHODEPLATE 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 
24th November 2013, 11:11 PM  #87 
diyAudio Member
Join Date: Feb 2009

[QUOTE=RajkoM;3715560]
Sorry for wrong paste, here is again **** 6J9P_4 ****************************************** * Created on 11/25/2013 00:58 using paint_kit.jar 2.6 * Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively * Plate Curves image file: 6j9p_4.jpg * Data source link: * .SUBCKT 6J9P 1 4 2 3 ; P K G2 G1 + PARAMS: CCG=8.5P CGP=0.03P CCP=3P RGI=2000 + MU=55.9 KG1=280.9 KP=369.1 KVB=23.1 EX=1.49 KG2=1147.5 * Vp_MAX=480 Ip_MAX=40 Vg_step=0.5 Vg_start=0.5 Vg_count=5 * Rp=1600 Vg_ac=23.5 P_max=7.5 Vg_qui=23.4 Vp_qui=240 UL=0.469 EG2=139.2 * X_MIN=73 Y_MIN=50 X_SIZE=365 Y_SIZE=256 FSZ_X=1032 FSZ_Y=742 XYGrid=false * showLoadLine=n showIp=y isDHT=n isPP=n isAsymPP=n isUL=n showDissipLimit=n * showIg1=y gridLevel2=n isInputSnapped=n * XYProjections=n harmonicPlot=y harmonics=y * RE1 7 0 1MEG ; DUMMY SO NODE 7 HAS 2 CONNECTIONS 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 4 3 VALUE={(EXP(EX*(LOG((V(4,3)/MU)+V(2,3)))))/KG2} RCP 1 3 1G ; FOR CONVERGENCE C1 2 3 {CCG} ; CATHODEGRID 1 C2 1 2 {CGP} ; GRID 1PLATE C3 1 3 {CCP} ; CATHODEPLATE 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 
25th November 2013, 12:07 AM  #88 
diyAudio Moderator

I needed to make some minor adjustments to KG2 because the screen grid current was lower than it should have been.
Interestingly enough the differences between my model and yours in LTspice were small with the exception of the screen grid current which based on the attached measurements is too low in both models. (Changing KG2 to 400 provides a reasonable approximation.)
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"To argue with a person who has renounced the use of reason is like administering medicine to the dead."  Thomas Paine 
25th November 2013, 01:39 AM  #89 
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25th November 2013, 03:41 PM  #90  
diyAudio Member
Join Date: Feb 2009

Quote:
Today I can see better than after midnight Best diying. 

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