So, I am using this model I downloaded (I think it is from KOREN), but while the Triode section model works great, the Pentode section is WAY OUT. Just doesn't work properly, at least in parafeed. Here it is:
.SUBCKT ECL84P 1 2 3 4 ; A G2 G1 C (Pentode)
* Philips Data Book sept 1968 AKA 6DX8
* library format: LTSpice 04-Feb-2009
X1 1 2 3 4 PENTODE1 MU=43.66 EX=1.350 KG1=344.3 KG2=4500 KP=201.06 KVB=26.0 VCT=0.00 RGI=2000 CCG=6.7p CPG1=0.6p CCP=4.1p ;
.ENDS ECL84P
I am designing an amp looking at the curves, as I am used to do, and I am using LTSpice to simulate and check. Does anyone has another model that might be working good? Or maybe someone could work something out?
I also tested the Koren models for ECL82 and ECL86 and compared with other ECL82/6BM8 and ECL86 models, and the Koren ones are also WAY OUT! So, I know the ECL84 model is probably wrong to, and it is not a problem with my simulation or circuit skills.
I know that making a pentode model is not something trivial, but I also know that there are guys out there that can do it, or maybe FIX that one that I posted here.
From using it, I think the problem in the model is related to the SCREEN. But can't be sure, really. Reading Spice model language is just like reading Chinese, Japanese or Arabic for me. I just can't do it...
I would be really, really, really thankful if someone could chime in and get these models working right, or maybe posting a better one. And all the community will have a new working model for this tube.
Thanks!
.SUBCKT ECL84P 1 2 3 4 ; A G2 G1 C (Pentode)
* Philips Data Book sept 1968 AKA 6DX8
* library format: LTSpice 04-Feb-2009
X1 1 2 3 4 PENTODE1 MU=43.66 EX=1.350 KG1=344.3 KG2=4500 KP=201.06 KVB=26.0 VCT=0.00 RGI=2000 CCG=6.7p CPG1=0.6p CCP=4.1p ;
.ENDS ECL84P
I am designing an amp looking at the curves, as I am used to do, and I am using LTSpice to simulate and check. Does anyone has another model that might be working good? Or maybe someone could work something out?
I also tested the Koren models for ECL82 and ECL86 and compared with other ECL82/6BM8 and ECL86 models, and the Koren ones are also WAY OUT! So, I know the ECL84 model is probably wrong to, and it is not a problem with my simulation or circuit skills.
I know that making a pentode model is not something trivial, but I also know that there are guys out there that can do it, or maybe FIX that one that I posted here.
From using it, I think the problem in the model is related to the SCREEN. But can't be sure, really. Reading Spice model language is just like reading Chinese, Japanese or Arabic for me. I just can't do it...
I would be really, really, really thankful if someone could chime in and get these models working right, or maybe posting a better one. And all the community will have a new working model for this tube.
Thanks!
Hmmm.... Although I do not understand it, I am messing around with it, and chancging the KG2 parameter from 4500 to 650 makes the tube work almost exactly as the datasheet curves predicts...
Could someone confirm it?
Could someone confirm it?
Would be like this:
.SUBCKT ECL84P-Correct 1 2 3 4 ; A G2 G1 C (Pentode)
* Philips Data Book sept 1968 AKA 6DX8
* library format: LTSpice 04-Feb-2009
X1 1 2 3 4 PENTODE1 MU=43.66 EX=1.350 KG1=344.3 KG2=650 KP=201.06 KVB=26.0 VCT=0.00 RGI=2000 CCG=6.7p CPG1=0.6p CCP=4.1p ;
.ENDS ECL84P-Correct
Do you think this looks right now, or am I deforming it even further?
.SUBCKT ECL84P-Correct 1 2 3 4 ; A G2 G1 C (Pentode)
* Philips Data Book sept 1968 AKA 6DX8
* library format: LTSpice 04-Feb-2009
X1 1 2 3 4 PENTODE1 MU=43.66 EX=1.350 KG1=344.3 KG2=650 KP=201.06 KVB=26.0 VCT=0.00 RGI=2000 CCG=6.7p CPG1=0.6p CCP=4.1p ;
.ENDS ECL84P-Correct
Do you think this looks right now, or am I deforming it even further?
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I don't think I can do it. Unless you have a tutorial on how to get LTSpice to Curve Trace a Tube. If you know how to do it and can take the time to teach me, or post a link to somewhere else with a description of the process, then I will do it.
But...
I tried my changed model with three totally different operating points, and it seems it is working just perfect, spot on, or at least very very close to what I predict and calculate when reading the datasheets.
But I don't know if my workaround might have generated other anomalies in distortion curves, etc...
But the original model had the Screen running with approximately 1/10th of the current it should be, and as a consequence, the rest of the parameters of the model was anything but right.
But...
I tried my changed model with three totally different operating points, and it seems it is working just perfect, spot on, or at least very very close to what I predict and calculate when reading the datasheets.
But I don't know if my workaround might have generated other anomalies in distortion curves, etc...
But the original model had the Screen running with approximately 1/10th of the current it should be, and as a consequence, the rest of the parameters of the model was anything but right.
Ok, as you can see the curves deviate from the datasheet all over the place, but is probably no worse than what the real tube would do given the manufacturing tolerance...
An externally hosted image should be here but it was not working when we last tested it.
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I work with this model and checked on uTRCER basically:
**********************************************
SUBCKT ECL84P 1 2 3 4 ; A G2 G1 C (Pentode)
*Vg2=170V
X1 1 2 3 4 PENTODE1 MU=34.768 EX=1.75 KG1=1030.0
KG2=477.5 KP=230.4 KVB=12.0 VCT=0.00 RGI=2000
CCG=6.7p CPG1=0.6p CCP=4.1p ;
.ENDS ECL84P
**********************************************
Attachments
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Thanks you for the input, guys.
I tried both models posted on LTSpice, and these doesn't work.
The pentode in the .txt file attached simulates, but gives very strange output. Also, I was very interested in the Pentode as Triode model, but it also seems very strange. Take a look at the KG1 parameter, for example: "KG1=¡Þ". Are you really using it???
The last model, when I add it to my Tubes.inc, won't even let file load.
I would also be interested in good ECL82, ECL83, ECL85 AND ECL86 models for trioeds, pentodes and also pentodes as triodes, but I mainly use LTSpice for tube sims. Does anyone have these?
I tried both models posted on LTSpice, and these doesn't work.
The pentode in the .txt file attached simulates, but gives very strange output. Also, I was very interested in the Pentode as Triode model, but it also seems very strange. Take a look at the KG1 parameter, for example: "KG1=¡Þ". Are you really using it???
The last model, when I add it to my Tubes.inc, won't even let file load.
I would also be interested in good ECL82, ECL83, ECL85 AND ECL86 models for trioeds, pentodes and also pentodes as triodes, but I mainly use LTSpice for tube sims. Does anyone have these?
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For the first one posted by Koonw, the pin order is wrong for LTspice. Below is the model with the correct pin order for LTspice.
As for the second one, it calls another subckt, namely 'PENTODE1', which LAZAROIU didn't include in his post. 😉
Code:
***** ECL84 ******************************************
* http://www.diyaudio.com/forums/tubes-valves/280457-good-ecl84-6dx8-tube-correct-pentode-spice-model-needed.html#post4468869
* Created on 10/01/2015 01:03 using paint_kip.jar
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file: ecl84.png
* Data source link: <plate curves URL>
*----------------------------------------------------------------------------------
.SUBCKT ECL84P 1 4 2 3 ; P G2 G K
+ PARAMS: CCG=3P CGP=1.4P CCP=1.9P RGI=2000
+ MU=43.5 KG1=615.6 KP=125.8 KVB=16.2 KVC=1.57 VCT=0.00264 EX=1.67 KG2=424.3
* Vp_MAX=250 Ip_MAX=60 Vg_step=0.5 Vg_start=0 Vg_count=9
* Rp=1600 Vg_ac=23.5 P_max=4.01 Vg_qui=-23.4 Vp_qui=240 UL=0.43 EG2=170.4
* X_MIN=74 Y_MIN=121 X_SIZE=1029 Y_SIZE=615 FSZ_X=1790 FSZ_Y=827 XYGrid=true
* showLoadLine=n showIp=y isDHP=n isPP=n isAsymPP=n isUL=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=n harmonicPlot=y harmonics=y
*----------------------------------------------------------------------------------
RE1 7 0 1G ; 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+(VCT+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)}
* Alexander Gurskii screen current, see audioXpress 2/2011
RE2 8 3 1G ; Dummy
G2 8 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG2*(KVC-ATAN(V(1,3)/KVB))}
E2 8 4 VALUE={0} ; Dummy
RCP 1 3 1G ; FOR CONVERGENCE
C1 2 3 {CCG} ; CATHODE-GRID 1
C2 1 2 {CGP} ; GRID 1-PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
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
*$
* The following triode model is derived from pentode model, see above.
* In the triode model, all spice parameters come directly from the pentode model, except for Kg1,
* which for triode-strapped pentodes is derived from pentode's Kg1, Kg2 and Kvc as
*
* 4Kg1Kg2 / (2Kvc-Pi)(2Kg1+PiKg2)
**** ECL84 ******************************************
* http://www.diyaudio.com/forums/tubes-valves/280457-good-ecl84-6dx8-tube-correct-pentode-spice-model-needed.html#post4468869
* Created on 10/01/2015 01:03 using paint_kit.jar 3.3
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file: ecl84.png
* Data source link: <plate curves URL>
*----------------------------------------------------------------------------------
.SUBCKT ECL84P-t 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=3P CGP=1.4P CCP=1.9P RGI=2000
+ MU=43.5 KG1=¡Þ KP=125.8 KVB=16.2 VCT=0.00264 EX=1.67
* Vp_MAX=250 Ip_MAX=60 Vg_step=0.5 Vg_start=0 Vg_count=9
* Rp=1600 Vg_ac=23.5 P_max=4.01 Vg_qui=-23.4 Vp_qui=240
* X_MIN=74 Y_MIN=121 X_SIZE=1029 Y_SIZE=615 FSZ_X=1790 FSZ_Y=827 XYGrid=true
* showLoadLine=n showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=n harmonicPlot=y harmonics=y
*----------------------------------------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G ; TO AVOID FLOATING NODES
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; POSITIVE GRID CURRENT
R1 2 5 {RGI} ; POSITIVE GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS
*$I've added on what I think may be the missing subckt call from LAZAROIU's post.
Code:
**********************************************
.SUBCKT ECL84P-laz 1 2 3 4 ; A G2 G1 C (Pentode)
* Vg2=170V
X1 1 2 3 4 PENTODE1
+ PARAMS: MU=34.768 EX=1.75 KG1=1030.0
+ KG2=477.5 KP=230.4 KVB=12.0 VCT=0.00 RGI=2000
+ CCG=6.7p CPG1=0.6p CCP=4.1p ;
.ENDS ECL84P-laz
**********************************************
*
**********************************************
.SUBCKT PENTODE1 1 2 3 4 ; A G2 G1 C
+ PARAMS: MU=95.39 EX=0.920 KG1=222.5 KG2=119 KP=860 KVB=19.1
+ VCT=0.00 RGI=2000 CCG=5.7p CPG1=0.560p CCP=2.5p
RE1 7 0 1MEG ; DUMMY SO NODE 7 HAS 2 CONNECTIONS
E1 7 0 VALUE={V(2,4)/KP*LOG(1+EXP((1/MU+V(3,4)/V(2,4))*KP))} ; E1 BREAKS UP LONG EQUATION FOR G1.
G1 1 4 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1*ATAN(V(1,4)/KVB)}
G2 2 4 VALUE={(EXP(EX*(LOG((V(2,4)/MU)+V(3,4)))))/KG2}
*G2 2 4 VALUE={PWR(if( V(2,4)/MU+V(3,4) < 0 , V(2,4)/MU+V(3,4), 0 ) ,EX )/KG2}
*G2 2 4 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG2*(2.5708-ATAN(V(1,3)/KVB))}
RCP 1 4 1G ; FOR CONVERGENCE A - C
C1 3 4 {CCG} ; CATHODE-GRID 1 C - G1
C2 1 3 {CPG1} ; GRID 1-PLATE G1 - A
C3 1 4 {CCP} ; CATHODE-PLATE A - C
R1 3 5 {RGI} ; FOR GRID CURRENT G1 - 5
D3 5 4 DX ; FOR GRID CURRENT 5 - C
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N) ;
.ENDS PENTODE1I do a pentode curve sweep, it matches well with the original. Do same plot using test circuit attached, see if you get the same result
Attachments
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These models are from Ayumi Nakabayashi's web site. You can download the zip file here:
http://ayumi.cava.jp/audio/pctube_1.11_win.zip
Please observe the copyright notice.
To use in LTspice, change all instances of ^ to **. Sorry about that! 😀
ECL85 Pentode section:
Pentode section triode connected:
Triode section:
http://ayumi.cava.jp/audio/pctube_1.11_win.zip
Please observe the copyright notice.
To use in LTspice, change all instances of ^ to **. Sorry about that! 😀
ECL85 Pentode section:
Code:
*
* Generic pentode model: ECL85P
* Copyright 2003--2008 by Ayumi Nakabayashi, All rights reserved.
* Version 3.10, Generated on Wed Oct 22 16:34:56 2008
* Plate
* | Screen Grid
* | | Control Grid
* | | | Cathode
* | | | |
.SUBCKT ECL85P A G2 G1 K
BGG GG 0 V=V(G1,K)+0.61401316
BM1 M1 0 V=(0.075869075*(URAMP(V(G2,K))+1e-10))^-1.148877
BM2 M2 0 V=(0.56627772*(URAMP(V(GG)+URAMP(V(G2,K))/5.7167203)))^2.648877
BP P 0 V=0.0037731888*(URAMP(V(GG)+URAMP(V(G2,K))/10.095259))^1.5
BIK IK 0 V=U(V(GG))*V(P)+(1-U(V(GG)))*0.0027774625*V(M1)*V(M2)
BIG IG 0 V=0.0018865944*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)*(0.935445718*(1-URAMP(V(A,K))/(URAMP(V(A,K))+10))^1.5+0.064554282)
BIK3 IK3 0 V=V(IK2)*(URAMP(V(A,K))+4320)/(URAMP(V(G2,K))+4320)
BIK4 IK4 0 V=V(IK3)-URAMP(V(IK3)-(0.0024608947*(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)-(0.0024608947*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 1p
CGK G1 K 5.1p
C12 G1 G2 3.4p
CAK A K 7.1p
.ENDS
Code:
*
* Generic triode model: ECL85PT
* Copyright 2003--2008 by Ayumi Nakabayashi, All rights reserved.
* Version 3.10, Generated on Wed Oct 22 16:34:56 2008
* Plate
* | Grid
* | | Cathode
* | | |
.SUBCKT ECL85PT A G K
BGG GG 0 V=V(G,K)+0.61401316
BM1 M1 0 V=(0.075869075*(URAMP(V(A,K))+1e-10))^-1.148877
BM2 M2 0 V=(0.56627772*(URAMP(V(GG)+URAMP(V(A,K))/5.7167203)+1e-10))^2.648877
BP P 0 V=0.0037731888*(URAMP(V(GG)+URAMP(V(A,K))/10.095259)+1e-10)^1.5
BIK IK 0 V=U(V(GG))*V(P)+(1-U(V(GG)))*0.0027774625*V(M1)*V(M2)
BIG IG 0 V=0.0018865944*URAMP(V(G,K))^1.5*(URAMP(V(G,K))/(URAMP(V(A,K))+URAMP(V(G,K)))*1.2+0.4)
BIAK A K I=URAMP(V(IK,IG)-URAMP(V(IK,IG)-(0.0024608947*URAMP(V(A,K))^1.5)))+1e-10*V(A,K)
BIGK G K I=V(IG)
* CAPS
CGA G A 4.4p
CGK G K 5.1p
CAK A K 7.1p
.ENDS
Code:
*
* Generic triode model: ECL85T
* Copyright 2003--2008 by Ayumi Nakabayashi, All rights reserved.
* Version 3.10, Generated on Wed Oct 22 16:34:55 2008
* Plate
* | Grid
* | | Cathode
* | | |
.SUBCKT ECL85T A G K
BGG GG 0 V=V(G,K)+0.53083873
BM1 M1 0 V=(0.0093163171*(URAMP(V(A,K))+1e-10))^-0.90408466
BM2 M2 0 V=(0.6239381*(URAMP(V(GG)+URAMP(V(A,K))/40.365941)+1e-10))^2.4040847
BP P 0 V=0.0035136299*(URAMP(V(GG)+URAMP(V(A,K))/64.695426)+1e-10)^1.5
BIK IK 0 V=U(V(GG))*V(P)+(1-U(V(GG)))*0.0022231252*V(M1)*V(M2)
BIG IG 0 V=0.0017568149*URAMP(V(G,K))^1.5*(URAMP(V(G,K))/(URAMP(V(A,K))+URAMP(V(G,K)))*1.2+0.4)
BIAK A K I=URAMP(V(IK,IG)-URAMP(V(IK,IG)-(0.0018385944*URAMP(V(A,K))^1.5)))+1e-10*V(A,K)
BIGK G K I=V(IG)
* CAPS
CGA G A 4p
CGK G K 2.7p
CAK A K 4p
.ENDS
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Hi,
Here are ECL83 and ECL86 Eg2 250/300V model and curve not found elsewhere. Koren_Tubes.inc contains most models but some are not so accurate, you should compare them. I'm not using them at the moment but i have checked ok. If any other model you need let me know.
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No... can't be that... I use many models that call for the Pentode1 and works fine, so it is loaded on my system somewhere.
About the other model, it is working, but not as good as the first one that I moded with my hit and miss technique. It works just fine with any KG2 volts and complaints with the curves in the datasheets... so, I am using it until I get something better.
Thanks for the other models! I will try those.
Really? Please see post #6, your version has poorer matching compared to the ones contributed by the other members.
I change KG2 from 424 to 4500, it does not make any difference to the plot, please compare attached with earlier plot. This implied KG2 is not used. My model tool is from http://www.dmitrynizh.com/tubeparams_image.htm#other_interactive_tools which is improvement over Koren's model, I think.
On the Finding SPICE tube model parameters pages it says:
"KG2 [4500] kG2 Inverse screen grid current sensitivity. NOT OPTIMIZED. The entered value is kept."
But in actual case plot of Koren's model makes the screen / plate current to reduce if KG2 is reduced as pointed out earlier. So one has to look into as where KG2 is used in the formula of calculation of Koren's model and that might solve the accuracy problem?
Attachments
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No, I'm unable to confirm it, according to my test sim putting 2 side by side, a change of KG2 does not make any difference to either model. It could be the improvement of Koren's model is more accurate as you can see formula for E1 & G1 is quite different.
IME ECL/PCL84 isnt a great tube for audio. Triode is OK, but pentode not so much and rather low in power for output stage, Be OK for a Pentode Mu follower I guess.
PCL/ECL85/805 is Much better, as was intended as Vertical osc/output in TV sets.--Just watch the VG2 volts, keep below 170v, a very tough valve, originally designed for monochrome TV but ended up in some 90 deg colour sets too.
--Most people forget a TV Vertical Output Stage IS an audio-amp stage, just optimized in circuit design for 50 or 60 Hz.....
--I prefer the ECL85/805 to any ECL/PCL86,--the 85/805 more reliable.
ECL/PCL86 IMHO is an unreliable turd--Horrible things!
PCL/ECL82 is probably one of the best and most reliable triode/pentode valves, Never seen a dead one, while I changed hundreds of the similar PCL86, due to distorted sound and 'pop-off'.
--PCL/ECL84 was normally used as Colour-Difference amp (CDA Drive) in first and second gen (UK) TV sets, and some earlier mono sets as Video output, and wouldn't be normally found in any audio-stage, I wouldn't consider using it myself for audio, seeing there's much nicer valves to be had.....
PCL/ECL85/805 is Much better, as was intended as Vertical osc/output in TV sets.--Just watch the VG2 volts, keep below 170v, a very tough valve, originally designed for monochrome TV but ended up in some 90 deg colour sets too.
--Most people forget a TV Vertical Output Stage IS an audio-amp stage, just optimized in circuit design for 50 or 60 Hz.....
--I prefer the ECL85/805 to any ECL/PCL86,--the 85/805 more reliable.
ECL/PCL86 IMHO is an unreliable turd--Horrible things!
PCL/ECL82 is probably one of the best and most reliable triode/pentode valves, Never seen a dead one, while I changed hundreds of the similar PCL86, due to distorted sound and 'pop-off'.
--PCL/ECL84 was normally used as Colour-Difference amp (CDA Drive) in first and second gen (UK) TV sets, and some earlier mono sets as Video output, and wouldn't be normally found in any audio-stage, I wouldn't consider using it myself for audio, seeing there's much nicer valves to be had.....
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