Surely though....
+B has already been applied to the tube--At the factory that made it during its testing.....?
I Do agree however,new/nos tubes should be run heaters only for 4-5 days, if nothing else, the heat helps the gettering of a tube thats stood for some years in a box......
According to this Article: The history of ORZEP (how radiolamps were made)
"From each batch of products, up to 1000 pieces, an arbitrary sample of 100 pieces was selected, which was checked for all parameters and appearance."
For American RCA Factory Tour • Vintage Tube Services
For military use all may adopt the same MIL-STD-1311 standard. OTK is similar to JAN which is acceptable for military standard. Not sure about Chinese -J military standard, I have tested more 60 pcs 6p14p-j, they're pretty consistence.
"From each batch of products, up to 1000 pieces, an arbitrary sample of 100 pieces was selected, which was checked for all parameters and appearance."
For American RCA Factory Tour • Vintage Tube Services
For military use all may adopt the same MIL-STD-1311 standard. OTK is similar to JAN which is acceptable for military standard. Not sure about Chinese -J military standard, I have tested more 60 pcs 6p14p-j, they're pretty consistence.
ef80 model found does not include screen current. I need to generate another model using Philips datasheet here, may take awhile. The screen voltage Vg2 option for model is 170v, 200v and 250v, so the screen voltage in the actual circuit should be about the same as the model, screen supply voltage may need adjusted. Anyway I can adjust in the sim. Do you have any preference for Vg2 voltage?
Also as there is no screen current included in datasheet, so I need to adjust the screen current so the pentode strapped triode curve close to this. First of course need reasonable accurate pentode model.
"OTK is similar to JAN" - wrong statement. OTK could be same "by sample testing", hence not military grade at all, but for civil use, though could be for both. The mil would likely have the special stamping, most often the diamond (with the number inside), sometimes as a star, or the "ВП" letters.
Here is the thing: some species were not made for civil use, hence for those OTK means yes, military grade only. The common ones like you mentioned 6П14П in order to be considered a "JAN" have to have that special stamping. Sometimes it was only on enclosed spec/datasheet inside the box of e.g. 50 pieces, which individually might have none.
Here is the sim with ef80, adjust the bias volt, no other components changed.
EF80 model in use:
EF80 model in use:
Code:
* Created on 06/29/2017 17:18 using paint_kip.jar
* [URL="http://www.dmitrynizh.com/tubeparams_image.htm"]Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively[/URL]
* Plate Curves image file: ef80.png
* Data source link: <plate curves URL>
*----------------------------------------------------------------------------------
.SUBCKT EF80 1 2 3 4 ; P G K G2
+ PARAMS: CCG=7.5P CGP=3.3P CCP=0.012P RGI=2000
+ MU=50 KG1=4334.4 KP=793.2 KVB=16.3 KVC=1.57 VCT=1.82 EX=2.24 KG2=16740
* Vp_MAX=350 Ip_MAX=50 Vg_step=1 Vg_start=0 Vg_count=5
* Rp=1600 Vg_ac=23.5 P_max=2.5 Vg_qui=-23.4 Vp_qui=240 UL=0.43 EG2=170
* X_MIN=64 Y_MIN=82 X_SIZE=953 Y_SIZE=689 FSZ_X=1942 FSZ_Y=1102 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
*$Attachments
Here ef80 screen current has been adjusted higher somewhat so the triode plot is closer to the reference mentioned earlier. The increase in screen current affect the bias, but looks within the range. Noted that screen voltage is about 170V.
Code:
**** EF80 ******************************************
* Created on 06/29/2017 18:54 using paint_kip.jar
* [URL="http://www.dmitrynizh.com/tubeparams_image.htm"]Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively[/URL]
* Plate Curves image file: ef80.png
* Data source link: <plate curves URL>
*----------------------------------------------------------------------------------
.SUBCKT EF80 1 2 3 4 ; P G K G2
+ PARAMS: CCG=7.5P CGP=3.3P CCP=0.012P RGI=2000
+ MU=50 KG1=4334.4 KP=793.2 KVB=16.3 KVC=1.79 VCT=1.87 EX=2.24 KG2=4854.6
* Vp_MAX=350 Ip_MAX=50 Vg_step=1 Vg_start=0 Vg_count=5
* Rp=1600 Vg_ac=23.5 P_max=2.5 Vg_qui=-23.4 Vp_qui=240 UL=0.43 EG2=170
* X_MIN=64 Y_MIN=82 X_SIZE=953 Y_SIZE=689 FSZ_X=1942 FSZ_Y=1102 XYGrid=true
* showLoadLine=n showIp=y isDHP=n isPP=n isAsymPP=n isUL=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=n harmonicPlot=y harmonics=y
*----------------------------------------------------------------------------------
RE1 7 0 1G ; DUMMY SO NODE 7 HAS 2 CONNECTIONS
E1 7 0 VALUE= ; E1 BREAKS UP LONG EQUATION FOR G1.
+{V(4,3)/KP*LOG(1+EXP((1/MU+(VCT+V(2,3))/V(4,3))*KP))}
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1*ATAN(V(1,3)/KVB)}
* Alexander Gurskii screen current, see audioXpress 2/2011
RE2 8 3 1G ; Dummy
G2 8 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG2*(KVC-ATAN(V(1,3)/KVB))}
E2 8 4 VALUE={0} ; Dummy
RCP 1 3 1G ; FOR CONVERGENCE
C1 2 3 {CCG} ; CATHODE-GRID 1
C2 1 2 {CGP} ; GRID 1-PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
R1 2 5 {RGI} ; FOR GRID CURRENT
D3 5 3 DX ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS
*$Attachments
We've been using Russian tubes for about 35 years. IME, there is always a number associated with the OTK stamp; the higher the number the better. Generally speaking though once the number was more than about 15 or so we had little troubles with the tubes.
But it was quite clear that the tubes we got, which were bulk packaged, came to us untested.
At any rate, if you want your tubes to last, do the preconditioning! I've been on both sides of that issue and the preconditioning has saved us a lot of failures. IOW, we found that we got a lot less arcing in new tubes by preconditioning.
But it was quite clear that the tubes we got, which were bulk packaged, came to us untested.
At any rate, if you want your tubes to last, do the preconditioning! I've been on both sides of that issue and the preconditioning has saved us a lot of failures. IOW, we found that we got a lot less arcing in new tubes by preconditioning.
i was thinking 8mA CCS at the cathodes of the 6bx6/ef80....
making the CCS adjustable to get the bias at the 6C33c grids produce the desired operating point..
What I really mean to say OTK is minimal requirement to acceptance into military. OTK system provided a first level of control, filtering out goods that were obviously substandard, and this freed the military agents to focus on the next level of screening as military agent so you see OTK form the dual regulation of the quality control. Likewise JAN stamp can do the same for US military.
Read this article if interested, but discussion maybe off topic, raise another thread if you wish.
I have just received a lot of 10 pcs 6c33c-v from Russia (1976 production) Do I have to burn in prior to check them ? Did anyone try this?
As Tim's OTL schedule seams to be somehow dependent on tubes matching, I intend to match them as close as possible using atached schematics. Did someone tried this kind of device?
regards
As Tim's OTL schedule seams to be somehow dependent on tubes matching, I intend to match them as close as possible using atached schematics. Did someone tried this kind of device?
regards
Attachments
My "Tim Mellow" OTL
Some minor changes
- Balanced Inputs
- Valvo ECC808 Input Triodes
- MCU controlled High-voltage delay (15 min. pre-heat )
- More capacitance in power supply
- Total star wiring (Hi-Volt, ground, heaters) - no hum with ears close to speaker at max. volume.
Thanks Tim, Perfect design!
Some minor changes
- Balanced Inputs
- Valvo ECC808 Input Triodes
- MCU controlled High-voltage delay (15 min. pre-heat )
- More capacitance in power supply
- Total star wiring (Hi-Volt, ground, heaters) - no hum with ears close to speaker at max. volume.
Thanks Tim, Perfect design!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
Maximum number is 9, from 5 to 9
(military -> marine - > military + humidity -> airforces -> space, nuclear)
Best is 9
