Mesh plate tubes

Zoran · 2025-06-21T08:32:16+0100

Rod Coleman said:
Good work, thank you!

With the 1920s valves, the Pa was not stated, because is is assumed that you run only Class-A, and use the maximim anode voltage (180V) and ½ the maximum anode current (=25mA) = 4,5W

For capacitances, we can use the values of the Mazda AC/HL.
AEI Mazda bought Met-Vick (COSMOS) in 1928, and the AC/HL was the newer version of the COSMOS AC/ valve

Cag = 3,5pF
Ca-> all: 7pF (anode to all earth-referred electrodes)
Cg-> all 7pF

Check out the history of the AC/HL here: Link-AC/HL
Read about the famous 250 000 hour BBC Mazda AC/HL! Worth a read.

Hi Rod
I checked Mazda AC/HL few days ago. Same method as for AC/R.
Graph click data points extraction.
.

.
Text Wrangler sorting datas
AC-HL DATAS GC.txt
.
MatLab modelling
(note that Ug starts from +1V not from 0V)
Again, very linear tube. But it is huge differents from AC/R type.
AC/HL has significantly higher mju factor of 35, and other parameters are different...
.

.
Check with the Tools
As You suggest I corrected Pa max to 1.2W ( Pamax x (Iamax/2) )
.

.
Capacitances from AC/HL Mazda datas
I put glass non-metallised data for booth tubes AC/HL and for AC/R

.
Spice models for AC/HL and for AC/R
.

Code:

*
**** AC-HL Mazda ******************************************
* Created on 06/19/2025 20:59 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*
* Ccg = 5.5P ; metalised 5.5P
* Cgp = 4.5P ; metalised 4.5P
* Ccp = 5.25P; metalised 7.5P
*
* Pa max. = maximum anode voltage (200V) and 1/2 the maximum anode current (=6mA) = 1.2W
* Va max. = 200V
* Ia max. = 12mA
* Uh=4V, Ih=1A
*
*----------------------------------------------------------------------------------
.SUBCKT AC-HL 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=5.5P  CGP=4.5P CCP=5.25P RGI=2000
+ MU=35.07 KG1=1302.1 KP=265.34 KVB=290 VCT=0.2 EX=1.346
*----------------------------------------------------------------------------------
* Vp_MAX=300 Ip_MAX=15 Vg_step=0.5 Vg_start=1 Vg_count=19
* Rp=24000 Vg_ac=1 P_max=1.2 Vg_qui=-2 Vp_qui=200
* X_MIN=67 Y_MIN=37 X_SIZE=760 Y_SIZE=646 FSZ_X=1635 FSZ_Y=802 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=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 AC-HL
*$
*
**** AC⁄R Cosmos Ind. H Triode ******************************************
* Created on 06/19/2025 16:41 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*
* Capacitances from AC-HL model, Mazda datas
* Ccg = 5.5P ; metalised 5.5P
* Cgp = 4.5P ; metalised 4.5P
* Ccp = 5.25P; metalised 7.5P
*
* Pa max. = maximum anode voltage (180V) and 1/2 the maximum anode current (=25mA) = 4.5W
* Va max. = 180V
* Uh=4V, Ih=1A
*----------------------------------------------------------------------------------
.SUBCKT AC-R 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=5.5P  CGP=4.5P CCP=5.25P RGI=2000
+ MU=10.29 KG1=2582.1 KP=61.28 KVB=463.27 VCT=0.2 EX=1.457
*----------------------------------------------------------------------------------
* Vp_MAX=300 Ip_MAX=50 Vg_step=2 Vg_start=2 Vg_count=11
* Rp=7000 Vg_ac=2.85 P_max=4.5 Vg_qui=-6 Vp_qui=155
* X_MIN=64 Y_MIN=27 X_SIZE=731 Y_SIZE=578 FSZ_X=1594 FSZ_Y=713 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=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 AC-R
*$

.
Cheers 🙂
.

Rod Coleman · 2025-06-21T10:35:18+0100

My apologies - the Mother of AC/HL was AC/G ( µ = 35 version of the AC/R). Mea Culpa.

Thank you for encoding the LTSPICE models!

@sser2 - it looks like the original price was too high! Especially with a depression coming.

Rod Coleman · 2025-06-21T10:37:42+0100

@Zoran - Does the encoder work with constant Ua curves ? I'm interested in the ME1401 - Link to ME1401 data, curves

banat · 2025-06-21T12:39:23+0100

According to my investigation microphony more resistant is very small Nuvistor valves , think because of very rigid internal structures .
http://www.r-type.org/articles/art-150.htm

Zoran · 2025-06-21T14:40:36+0100

banat said:
small Nuvistor valves

Hi Banat 🙂 how are You didnt cross each other for long time - cheers

Zoran · 2025-06-21T14:51:23+0100

Rod Coleman said:
the Mother of AC/HL was AC/G

Hi Rod yes but still there are some diferences?

.
With same procedure I made another model for AC/G
in the AC-G GC DATAS.txt file datas stored.
.

.
I additionaly made little improvements from MatLab starting model with tools. To make anode curves crossing as close to the extracted datas.
.

.
There is a spice model:
.

Code:

****  AC-G Mazda ******************************************
* Created on 06/21/2025 15:01 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*
*  Ug step 1V, from +1V to -8V
*
*  capacitances from AC/HL Mazda type
*  Ccg = 5.5P ; metalised 5.5P
*  Cgp = 4.5P ; metalised 4.5P
*  Ccp = 5.25P; metalised 7.5P
*
*  Pa max. = Va max x Ia max / 2 = 1.1W
*  Va max. = 180V
*  Ia max. = ?
*  Uh=4V, Ih=1A
*
*----------------------------------------------------------------------------------
.SUBCKT AC-G 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=5.5P  CGP=4.5P CCP=5.25P RGI=2000
+ MU=39 KG1=1030.14 KP=210.06 KVB=2692.66 VCT=0.2 EX=1.092
*----------------------------------------------------------------------------------
* Vp_MAX=300 Ip_MAX=15 Vg_step=1 Vg_start=1 Vg_count=12
* Rp=22000 Vg_ac=1 P_max=1.1 Vg_qui=-2 Vp_qui=175
* X_MIN=51 Y_MIN=34 X_SIZE=729 Y_SIZE=645 FSZ_X=1590 FSZ_Y=763 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n 
* XYProjections=y harmonicPlot=y dissipPlot=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 AC-G
*$

.
Very good tube, but almost unobtainable 🙁
A have some AC102 triodes I will compare to the "AC" Mazda types...
Cheers
.

Zoran · 2025-06-21T15:03:47+0100

Sorry to going off-topic?
There is one more tube from Mazda AC series but with higher mju factor.
AC2-HL
.

.

.
There are 2 spice models one from MatLab other improved with tools soft.

Code:

*
****  AC2-HL matlab model improved  ******************************************
* Created on 06/21/2025 15:18 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*
* Ug step 1V, from +1V to -8V
*
* capacitances
* Ccg = 9P
* Cgp = 6.5P
* Ccp = 6P
*
* Pa max. = Va max x Ia max / 2 = 1.4W
* Va max. = 200V
* Ia max. = 14mA
* Uh=4V, Ih=1A
* mu=75
*
*----------------------------------------------------------------------------------
.SUBCKT AC2-HL 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=9P  CGP=6.5P CCP=6P RGI=2000
+ MU=76.76 KG1=487.2 KP=309.93 KVB=100.58 VCT=0.132 EX=1.49
*----------------------------------------------------------------------------------
* Vp_MAX=300 Ip_MAX=15 Vg_step=0.25 Vg_start=1 Vg_count=25
* Rp=27000 Vg_ac=0.25 P_max=1.4 Vg_qui=-0.5 Vp_qui=150
* X_MIN=67 Y_MIN=25 X_SIZE=796 Y_SIZE=679 FSZ_X=1668 FSZ_Y=786 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n 
* XYProjections=y harmonicPlot=y dissipPlot=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 AC2-HL
*$
*
* 
****  AC2-HL_ML matlab model ******************************************
* Created on 06/21/2025 15:18 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*
* Ug step 1V, from +1V to -8V
*
* capacitances
* Ccg = 9P
* Cgp = 6.5P
* Ccp = 6P
*
* Pa max. = Va max x Ia max / 2 = 1.4W
* Va max. = 200V
* Ia max. = 14mA
* Uh=4V, Ih=1A
* mu=75
*
*----------------------------------------------------------------------------------
.SUBCKT AC2-HL_ML 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=9P  CGP=6.5P CCP=6P RGI=2000
+ MU=79.96 KG1=464 KP=303.85 KVB=101.6 VCT=0.2 EX=1.342
*----------------------------------------------------------------------------------
* Vp_MAX=300 Ip_MAX=15 Vg_step=0.25 Vg_start=1 Vg_count=25
* Rp=27000 Vg_ac=0.25 P_max=1.4 Vg_qui=-0.5 Vp_qui=150
* X_MIN=67 Y_MIN=25 X_SIZE=796 Y_SIZE=679 FSZ_X=1668 FSZ_Y=786 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n 
* XYProjections=y harmonicPlot=y dissipPlot=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 AC2-HL_ML
*$
*

Zoran · 2025-06-21T16:08:43+0100

Rod Coleman said:
@Zoran - Does the encoder work with constant Ua curves ? I'm interested in the ME1401 - Link to ME1401 data, curves

Hi Rod
This is very special little tube.
For now I only find some model but not accurate in whole range... 🙁
Only in the mid-upper region as You can spot.
With Tools soft.
Where in the operating region You want to use this tube?
Probably in linear region gravitating to the "top" of the graph?
.
I will try to extract point values and put in the MatLab soft to check.
Grid currents probably be very hard to model?
.
Start models for ME1401, DHT and plain triode
.

.

Code:

****  Composite DHT *****************************************
* Created on 06/21/2025 16:51 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*----------------------------------------------------------------------------------
.SUBCKT ME1401_DHT_start 1 2 3 4 ; P G K1 K2
+ PARAMS: CCG=0.6P  CGP=20P CCP=0.8P RFIL=96.15
+ MU=2.5 KG1=1785.6 KP=10.35 KVB=348 VCT=-8.888 EX=1.344 RGI=2000
* Vp_MAX=14 Ip_MAX=0.2 Vg_step=0.5 Vg_start=-2 Vg_count=4
* Rp=68000 Vg_ac=0.1 P_max=0.0025 Vg_qui=-2.75 Vp_qui=11
* X_MIN=72 Y_MIN=34 X_SIZE=1007 Y_SIZE=580 FSZ_X=1881 FSZ_Y=709 XYGrid=true
* showLoadLine=y showIp=y isDHT=y isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n 
* XYProjections=y harmonicPlot=y dissipPlot=y
*----------------------------------------------------------------------------------
RFIL_LEFT    3  31 {RFIL/4}
RFIL_RIGHT   4  41 {RFIL/4}
RFIL_MIDDLE1 31 34 {RFIL/4}
RFIL_MIDDLE2 34 41 {RFIL/4}
E11 32 0  VALUE={V(1,31)/KP*LOG(1+EXP(KP*(1/MU+V(2,31)/SQRT(KVB+V(1,31)*V(1,31)))))}
E12 42 0  VALUE={V(1,41)/KP*LOG(1+EXP(KP*(1/MU+V(2,41)/SQRT(KVB+V(1,41)*V(1,41)))))}
RE11 32 0 1G
RE12 42 0 1G
G11 1 31 VALUE={(PWR(V(32),EX)+PWRS(V(32),EX))/(2*KG1)}
G12 1 41 VALUE={(PWR(V(42),EX)+PWRS(V(42),EX))/(2*KG1)}
RCP1 1 34 1G
C1 2 34 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 34 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; FOR GRID CURRENT
D4 6 4 DX ; FOR GRID CURRENT
RG1 2 5 {2*RGI} ; FOR GRID CURRENT
RG2 2 6 {2*RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS ME1401_DHT_start
*$

 
****  ******************************************
* Created on 06/21/2025 16:51 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*----------------------------------------------------------------------------------
.SUBCKT ME1401_start 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=0.6P  CGP=20P CCP=0.8P RGI=2000
+ MU=2.5 KG1=1785.6 KP=10.35 KVB=348 VCT=-8.888 EX=1.344
* Vp_MAX=14 Ip_MAX=0.2 Vg_step=0.5 Vg_start=-2 Vg_count=4
* Rp=68000 Vg_ac=0.1 P_max=0.0025 Vg_qui=-2.75 Vp_qui=11
* X_MIN=72 Y_MIN=34 X_SIZE=1007 Y_SIZE=580 FSZ_X=1881 FSZ_Y=709 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n 
* XYProjections=y harmonicPlot=y dissipPlot=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 ME1401_start
*$

Rod Coleman · 2025-06-21T16:49:55+0100

Zoran said:
Where in the operating region You want to use this tube?

Yes, only in the anode current > 75uA, or the linear current, and only 9 - 14V maximum.

The grid current - I don't care. For my application, it's always zero.

Thank you very much!

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