I don't think EF 86, 183, 184 & 30F5 are mesh plate tubes . I believe the mesh you see is screen/shield for RF pentodes. The internal structure including plate is inside the mesh.
Take a look at data sheets like that for 30F5 .
Take a look at data sheets like that for 30F5 .
I think EF183, EF800, etc, are all variants of EF80, and there is an interesting page here on the construction from Valve Museum: The Making of the EF80.
The anodes are quite small compared to the screen, and the screen is connected to an external pin, so might be an interesting experiment to try to use the screen as an anode, although hard to see how the anode structure could be neutralised. Maybe tie that to cathode + suppressor?
The anodes are quite small compared to the screen, and the screen is connected to an external pin, so might be an interesting experiment to try to use the screen as an anode, although hard to see how the anode structure could be neutralised. Maybe tie that to cathode + suppressor?
My mistake for suggesting the mesh was the anode. I forgot what I knew 20 years ago... Mea culpa .
Maybe the anode sheet could be used as Grid.2, along with the existing one; the use screen as anode. The screen mesh is not treated with a radiative surface, so the power level needs to be watched.
However, none of the IF pentodes with a mesh screen can match the Brimar 6BW7. This one has a solid sheet 360⁰ shielding screen.
In pentode mode it measures and sounds very fine - the best budget driver for a low mu power DHT by a long way.
Maybe the anode sheet could be used as Grid.2, along with the existing one; the use screen as anode. The screen mesh is not treated with a radiative surface, so the power level needs to be watched.
However, none of the IF pentodes with a mesh screen can match the Brimar 6BW7. This one has a solid sheet 360⁰ shielding screen.
In pentode mode it measures and sounds very fine - the best budget driver for a low mu power DHT by a long way.
RENS 1374D german pentode with mesh anode and mesh screen. Here the mesh anode
1930................full-wave rectifier vacuum tube manufactured by Telefunken
I used to have quite a few AZ1 mesh rectifiers which sounded great. The problem was those awful side contact sockets which eventually meant a lot of the tubes ended up with loose bases. Plus the Chinese sockets simply didn't work at all - I had to bin a whole bunch.
So I preferred using AZ11 meshes with their Y8A sockets which I like a lot. Their construction is a bit different though they resemble AZ1 electronically. I have a few for sale if interested, including these. Obviously cheaper directly from me...
https://www.ebay.co.uk/itm/146422533861?
https://www.ebay.co.uk/itm/146422543772?
https://www.ebay.co.uk/itm/146422541982?
So I preferred using AZ11 meshes with their Y8A sockets which I like a lot. Their construction is a bit different though they resemble AZ1 electronically. I have a few for sale if interested, including these. Obviously cheaper directly from me...
https://www.ebay.co.uk/itm/146422533861?
https://www.ebay.co.uk/itm/146422543772?
https://www.ebay.co.uk/itm/146422541982?
Just ordered a G1064 VALVO TUBE to try, looks very interesting! I also have a customer wanting me to build him a 300B amp with a new mesh plate EML 5U4G. Be interesting to work with that tube!
JYL WE2A3-G, definitely mesh no?
JYL has mesh 274Bs as well! sweet
No. What you see there is a static shield that's been used in many other, even much older tubes. The plates consist of two little sheets of solid metal within that shield. OTOH, TELFUNKEN EF183's and the likes show solid metal shields instead.
Best regards!
RENS1374D spice model
graph in datasheet was not scaled good i corrected it and scan the point values.
There are Ia and Ig2 values, in triode mode when G2 conneted to anode, Total Ia, in triode mode is a sum.
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Matlab estimated model based on datas.
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Corrected Matlab model with tools. Very useful tube for preamp and driver
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graph in datasheet was not scaled good i corrected it and scan the point values.
There are Ia and Ig2 values, in triode mode when G2 conneted to anode, Total Ia, in triode mode is a sum.
.
.
Matlab estimated model based on datas.
.
.
Corrected Matlab model with tools. Very useful tube for preamp and driver
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Code:
**** RENS1374D_triode ******************************************
* Created on 07/06/2025 15:28 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*
* no capacitances datas !!! estimated in model
* Ccg = P
* Cgp = P
* Ccp = P
*
* Pa+g2 max. = 6W
*
* Va Vg2 max. = 250 V
* Ia max. = 24 mA
* Ig2 max. = 10 mA
*
* Uh=4V Ih=1.1A
*
*----------------------------------------------------------------------------------
.SUBCKT RENS1374D_triode 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=3P CGP=1P CCP=3P RGI=2000
+ MU=8.5 KG1=1978.81 KP=67.2 KVB=111.47 VCT=0.235 EX=1.376
*----------------------------------------------------------------------------------
* Vp_MAX=350 Ip_MAX=60 Vg_step=3 Vg_start=3 Vg_count=20
* Rp=6800 Vg_ac=3 P_max=6 Vg_qui=-9 Vp_qui=163
* X_MIN=75 Y_MIN=38 X_SIZE=820 Y_SIZE=581 FSZ_X=1635 FSZ_Y=696 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 RENS1374D_triode
*$I dare to claim that an amplifier that allows you to listen to it's rectifier and identify different rectifiers by their »sounds« is a very, very poorly designed one. Guitar amplifiers might be the exception.
AZ1, AZ11, AZ21 all were descendants of the venerable Telefunken RGN1064 or Philips/Valvo G1064, with exactly the same data and behaviour. The mesh plates we see in some of them just represent the manufacturing technology they had at the time and had nothing to do with better heat transfer. Btw, what inside the plate would benefit from better heat transfer in a rectifier tube?
Anyway, if someone thinks a mesh plate tube has a more transparent sound signature, that's fine for me. But it's just expectation biased.
Best regards!
"Anyway, if someone thinks a mesh plate tube has a more transparent sound signature, that's fine for me. But it's just expectation biased."
So if someone does hear something, you are saying that they aren't?
I honestly didn't believe differences in speaker cables and other audio related gear many claim to be "Expectation bias" and thought the same thing. But the deal was I didn't expect to hear anything when I changed my speaker cables and I did, and the more expensive cable sounded worse... Was that also expectation bias?
So if someone does hear something, you are saying that they aren't?
I honestly didn't believe differences in speaker cables and other audio related gear many claim to be "Expectation bias" and thought the same thing. But the deal was I didn't expect to hear anything when I changed my speaker cables and I did, and the more expensive cable sounded worse... Was that also expectation bias?
I would dismiss "expectation bias" as pop psychology or not even that. It's just a useful excuse in audio threads when trying to make a case for you're being right. As in "I know I'm right here so........ ah yes, it must be expectation bias. That ought to explain it."
If you seriously want to talk about expectation bias I would expect you not only to have some training in academic psychology but also to have read a number of papers on the subject. It really, really is not that simple.
If you seriously want to talk about expectation bias I would expect you not only to have some training in academic psychology but also to have read a number of papers on the subject. It really, really is not that simple.
0A2 mesh plate regulator tube. Not the easiest to find but they do exist.
Was there a special designation for that 0A2? There are some 'M' and 'CV' variants. The 150C2 picture on Radiomuseum looks to be similar.
I can understand that there might be changes to the sound of music that are hard to explain when using certain tubes, special wires, etc, but the bit I struggle with is that there is no way to record the difference using measuring equipment.
Is this because it is impossible to measure those systems without influencing the output? Or is the difference an attribute that can never be measured?
I'm a measurement guy, but I do recognise that we do not usually measure using complex signals. Maybe some do, but I don't. We do not measure distortion, damping, gain etc using real music. Typically it is a nice sinus, or a mix of two tones, a square wave etc. Therefore, while I'm a bit sceptical about things like, for example, hearing the difference between two high quality polypropylene coupling caps, I cannot completely dismiss it. I keep my mind open, makes my life easier 🙂