This calculator allows you to trace the anode characteristics graph, and to compute and tune loadline and operating point of various vacuum tubes.
It considers both reactive loads and resistive load.
You can:
- choose among most common vacuum tubes (I am slowly adding more),
- set the operation modality, among ultralinear, pentode, and triode (suppressor tied to cathode) mode,
- set Single-Ended or Push-Pull configuration
- set the load type as reactive or resistive
- set the Power Supply V+ voltage, the screen voltage, the screen tap, the quiescent bias current.
- set the output headroom
The calculator:
- plots the anode characteristic graph, for the chosen operation modality,
- plots the reactive loadline for reactive load,
- plots the DC and AC loadlines for resistive load,
- highlights the operating point,
- highlights the needed output headroom, if set,
- estimates the grid bias voltage,
- estimates the expected power at the load when max Grid Voltage is the maximum displayed, when max Grid Voltage is 0, when operating in Class A or A2, and at the selected output voltage headroom.
- estimates the Harmonic Distortion (HD) in the operating range corresponding to the selected output headroom
Did you buy my book? Remember to leave a review on amazon!
Operating mode: | PP/SE: | ||
V+ (V): | Grid Bias Voltage (V): | ||
Quiescent Operating Point: |
Iq(mA): Vq(V): |
Output Power (W): | |
Load (Ohm): | |||
Next stage AC Impedance (Ohm): | HD%: | ||
Screen Voltage (V): | |||
UltraLinear tap (%): | |||
Out. headroom (+/-V): |
If you are not familiar with loadlines, their purpose, and their use, I suggest you checking my guide: Section 3.2 (for resistive loadlines), Section 4.1.3 (for reactive loadlines), and Section 4.2.2 (for AC loadlines).
The underlying model and equations, for tracing anode characteristics curves, are those discussed by Norman Koren, in his web site.
Very useful calculators! Thanks for your hard work. Any chance of adding 6l6gc and perhaps 6v6 to the list?
Hi I recently added 6l6g. 6v6 will be added in the future
6V6 is also there
Thank you for this!
Thank you
Thanks ot! Are the submini 6021 tubes also covered?
Not yet! 6021 is now in my pending list
6021 is now available
Kindly add 6BK5 to your choices
6BK5 is now available!
Very helpful calculator. Which tubes are you planning to add? How might I help?
Thanks for appreciating it. I recently addedd 6l6g, kt77, 6h30, kt150.
Do you have any suggestions?
Adding 6SQ7, 6888, and 7AK7 would be useful for me, thank you.
Thanks. I added them to my todo list
6SQ7 and 6888 and 7AK7 are ready in the calculator
Grazie e buona salute a te!
Could you add 6GM8? Thank you.
Done!
I appreciate your work here! Perhaps you should do a Patreon? I would certainly donate to this project. I use 6sl7 and 6sn7 quite a bit for preamp and phase inverter duty. Would love to 6v6 on here as well. Thank you!
6V6 just added. 6sl7 and 6sn7 are on waiting list 😉
6sl7 and 6sn7 are now available as well.!
Great job! This thing is so useful. Is there a chance to add 6AK6, ECL82 and ECL86?
Thanks in advance, brother.
I will try when back from vacation.
Merry Christmas!
Looking forward to it. Merry Christmas to you too!
Done! Check it!
Great! Thanks! This is definitely going to in handy. Because the 6AK6 can be used as a power valve, could you also add it with a reactive load? Thanks in advance .
Done!
You, sir, are great! Grazie mille 🙂
It is now possible choosing resistive or reactive load for every tube, in the Universal Loadline Calculator.
How difficult would it be to implement parallel valves? Could it be as simple as maybe a tick box to double the current scale and push the load line down?
Hi, as I explained in a post in Loadline calculator for power stages, when you attach a load to n parallel tubes, each tube simply sees n-times the load. The calculator computes the loadline of of a single tube. To use this calculator to compute your loadline, with parallel tubes, simply specify n-times the overall load.
Hi Giuseppe, I don’t know if it’s easy to do but having some double triodes on reactive loads would be a hell of and add-on ! I’m thinking 6SN7 push pull, 12AU7 push pull… Maybe it is possible since you have the models? That would be nice!
Your simulator is so much quicker than opening Orcad or another spice simulator.
Thanks for the amazing work !
The Universal Loadline Calculator now allows switching between resistive and reactive load for every tube.
Thanks Giuseppe for this amazing calculator. I was just checking it against a 2A3 data sheet and they match beautifully. Any chance of adding the JJ 2A3..?
2A3-40 JJ is now available.
nice tool … great job!!! Any chance of adding the 6550 and kt120 tungsol ?
Thanks!!!!
They are in the pending list. Hope to be able to add them soon.
6550 added!
KT120 still pending
KT120 done as well!
You are the best ! Thank you very much!! Amazing tool !!
🙂
Great job! My congratulations! I would also like to see EL86, 6AH6 and other, less common tubes, such as A2134.
Best regards!
Hi,
I’ll put them in the list. Hope to be able to add them soon.
Thanks for your feedbacks.
Thanks! Add 12E1 if possible)
Best regards!
12E1 just added
Many thanks!)
6AH6 added!
Thanks!
EL86 just added
Many thanks!
A2134 ready as well
Fantastic)
😉
Hello, is the Max Power RMS or peak Watts?
Hi,
it is a rough approximation of the output power when producing a sine wave ranging up to the saturation of the valve (for instance when reaching Vg=0) along the loadline.
More details are given in section 6.1.1 of my guide here: https://www.vtadiy.com/book/chapter-6-step-by-step-design-of-a-push-pull-tube-amplifier/6-1-design-of-the-power-stage/
Hope this is useful.
Hello Giuseppe, greetings from Greece
This online curve calculator is a really nice work, congrats!
Can you please add GM70 & GU50 to your list with positive grid curves
Keep going with all good fortune
Cheers
Thanks!
Addedd to the todo list … the list is becoming long 🙂
I just added GM70.
However, I did not find positive curve datasheet for this triode. Do you have it?
GU-50 added as well
Hi can you please add 6GU7 6CG7 12BH7
Hi, I added them to the todo list as well. Be patient 🙂
12BH7 is now available
6GU7 is also there
… and 6CG7 is ready … also with positive grid
Dear all,
thanks for using this calculator and thanks for suggesting additional tubes.
The pending list of tubes that will be added now includes:
ECL84, ECL85
kt120
EL86, 6AH6, A2134, 12E1
GM70, GU50
6GU7 6CG7 12BH7
45, 101D, 205D
Hope to be able to add them all in a couple of weeks.
Looking forward to. Thank you very much!
Is it possible to add 6K6GT to the list as well? Thank you!
Sure!
I added it to my pending list.
Thanks
6K6GT is now ready
Added 6AQ8 (ECC85)
12AT7 (ECC81) and 6J5, are now available in the calculator.
6J5 can also be tested with positive grid (however double check limiting values in the official datasheet http://www.r-type.org/pdfs/6j5.pdf )
Very nice tool Giuseppe!!! When I compare tubes it seems for example EL34 use 0V as Control Grid voltage when this calculates Power so Anode Current comes lower and Anode Voltage higher than for example 6L6GC which use +15V Controd Grid voltage. I just bought your Kindle book which I hope explains how it is possible to use CG positive values…
Sorry Giuseppe! Now the previous comments did open for me to read and you have already pointed to chapter where it is explained.
Perfect! 🙂
thank you for your calculator. can you please add 6AQ5/6005/EL90
Thanks. I added them to my todo list
Grazie tante per questa cosa.
Grazie a te 🙂
Done! Try it. 🙂
Hi,I want 6N7/6N7P/6H7C tube, Could You Add it?
Added to my todo list
And 807 tube
Hi, note that 807 is available since some days.
However, I still need some time for 6N7/6N7P/6H7C. There are others head in the list 🙂
Thanks I seen.
6N7/6N7P/6H7C are Same Tube ,6N7 is US Model,6N7P is China Model,6H7C is Soviet Model. It’s use for the low power Class-B PP.
6N7 added!
Please add 829B tube, thanks Vince
Added to my, now long, todo list 🙂
829B was already available. However I took the opportunity to refine the model.
Hello, Giuseppe! If possible, please add E180F and EL803S. I will be very grateful!
In the todo list … be patient 🙂
Thanks! 🙂
Thanks for 6JN6)))
E180F and EL803 added
Many many thanks!
Buongiorno Giuseppe, complimenti per il tuo lavoro!!! Potresti aggiungere la 845? per la 211 e 845 sarebbe interessante qualche valore di griglia positiva!
Grazie
Hi Feliciano, addedd to my pending list.
Thanks!
Tra l’altro, considera che per la 211 ci sono già le curve con valori positivi di griglia.
By The way, note that 211 already has positive grid values available.
845 Ready!
Hello, Giuseppe! Is your pending list empty?)
Hi Dimitri,
Currently I have these in my pending list (sorted according to request date):
829B, E180F, EL803S, EC8020, E55L, 5881,Ck6336
Best regards
Very interesting list. Thank you very much!
This is so useful. thankyou! Any chance you could add 6au6? Thanks again.
Thanks!
Addedd to my pending list
6AU6 just addedd and available to be used
Ciao Giuseppe,
could you please also add 12AY7 and ECC808? Thanks for all you do, it’s really very useful
Antonio
Hi Antonio,
Thanks! Added to my to do list. Be patient 🙂
12AY7 is now available.
Thank you so much Giuseppe!
ECC808 available as well
Great! I’ll wait, no problem. Good Easter
Hi, can you add 3A5 (DCC90) with sections is parallel? And 4P1L triode strapped.
Added to my todo list! Thanks
Anything? Regards
Hi Tomislav,
here is my pending list: EFL200/PFL200 , 2AY7 ECC808, 3A5 (DCC90), PX25, 300BXLS, T100, 12AT7/6072, 5902/6p30b, 6n16 and 6n17, 6C41, 6U8A, 6528.
Just a few, before your 3A5. Be patient 🙂
Thanks.
3A5 is now available
Thank you!
4P1L is ready as well. However, be carefull. In my model, triode mode is with G3 connected to to ground. I saw some curves, obtained with curve tracers, where 4P1L triode mode was plotted using G3 connected to anode, resulting in much higher current. Take this into account, if you compare my curves with those.
Hi Giuseppe.
Why I cannot set both Iq and Vq using my “own” values?
If I set Iq, the tool automatically calculates Vq and related Grid Bias Voltage or if I set Vq, the tool automatically calculates Iq and related Grid Bias Voltage.
My desire is to put my pair of Iq and Vq values, then obtaining Grid Bias Voltage from tool.
Thanks.
Hi Federico,
Once you fix the load and V+, then Vq and Iq are dependent one from the other becouse the Ohm Law: Iq=(V+-Vq)/load.
So, if you modify one of the two, the other follows from the Ohm Law and cannot be chosen arbitrarily. The result is that Vq and Iq are constrained to move along the loadline.
The calculator in addition computes the Grid Voltage needed to obtain the chosen pair (Vq,Iq).
Hi Giuseppe, you are right!
I often forgot the role of load line..
Nifty tool thank you !
Could you please add 12AT7/6072
Added to my pending list
12AT7 and 6072 (12AY7) are available
Hi. Thanks for that. It’s really helpful solution for designing and understanding valve amps.
I appreciate your job.
Is it possible to add there 6c41 tube? I have a datasheet if you need.
Regards
Thanks!
Added to my todo list. If you already have a datasheet, it would make things easier to me.
Hi,
6c41c is now available to be tested
THANK YOU GIUSEPPE.YOU SAVED US FROM A LOT OF CALCULATION TIME.THE TUBE 6U8A IS A VERY HANDY TUBE COULD YOU PLEASE ADD IT TO YOUR LIST?
Thanks a lot for appreciating my effort. I added the 6U8A to my (increasing 🙂 ) todo list.
6U8A (both triode and pentode sections) finally addedd to the calculator.
could you at 6sk7 6ba6 6j7 6sj7 6au6
Hi Arash,
note that 6sj7 and 6au6 are already available.
I added the others to my pending list.
6J7 ready!
Hi Giuseppe,
Hope you’re doing well.
I have a question, some tubes (like PCC88 and 6N7) show positive grid voltage curves.
I am a little confused by these, does this mean that these are still usable?
The reason why I am asking, is that the ECC88 for example doesn’t show these, while it’s basically the same tube (different heater voltage).
The result is that the calculated output power is a lot higher??!!??
Positive grid voltages should be used according to the guidelines in the datasheet. When in my graphs I show positive grid curves is because these are shown also in the datasheet. However, for using them carefully check the datasheet. Input impedance changes significantly with positive grid values, so circuits should be carefully designed for this.
For what concerns output power. In the last version of my calculator, I show various values, corresponding to output voltage swing along the loadline up to: max grid value displayed, grid equal to 0, class A/A2, and power at the specified headroom.
Thanks.
So practically for a Class-AB push-pull does this means I have to look at the grid equal to 0 (= g1), or is it also possible those valves to a positive grid?
Positive grid is possible both in Class A2 and AB2. Soecifically, class A means that the tube does not cut-off. It corresponds to a headroom around the operating point that does not arrive to tube cut-off. This might happen within negative grid (Class A) or positive grid (Class A2). In Class AB (negative grid) and AB2 (also positive grid), in turn one of the two tubes might cut-off, for a limited time, when delivering high output power.
Thanks, and it just depends on the tube if they can handle positive grid voltages?
So why isn’t there a positive grid for the ECC88 but there is for the PCC88 ?
To give a practical example, let’s put the PCC88 in PP mode, with V+ of 150V, reactive load of 15k and bias current of 8mA
According to this calculator, I should get 2.53W out of a PP PCC88, is that correct? Or am I just missing something?
Hi,
In fact there was an imprecision in the PCC88 model. The Philips PCC88 datasheet does not mention the possibility of positive grid. So I removed the option of choosing positive grids for this model.
When I built it I used the E88CC as basis, which is very similar and also allows positive grid values.
Now it should be fine.
Giuseppe! can you add 811A ? thaks
Added to may, now veeeery long, pending list.
I have been quite busy during last month and the pending list is now very long.
Can you do JJ’s 6V6S? While it is VERY similar to the 6V6GT it does have higher voltage tolerance as well a high plate dissipation.
Added to my long pending list
Dear firends,
recentely I have been very busy so my list of tubes to add became very long. Sorry for taking so long to satisfy you requests.
Currently my pending list contains:
ECC808, 3A5, 4P1L, PX25, 300BXLS, T100, 5902, 6p30b, 6n16, 6n17, 6C41, 6U8A
6528, 6sk7, 6ba6, 6j7, 6Y6, 811A, 2E22, 6dq6b, 6gw6, 6V6S
Hi Giuseppe!
Can you please add 811A?
Hi Arash,
It is in my pending list … there are a few haed of it still waiting … pe patient 🙂
Hi,
811A is now available.
Giuseppe Amato , how are you ? With a 807 tube , 4200ohm load, 350V 75mA. Do you think is a good point of work ?
Hi,
if you want Class A, probably yes. Elsewhere, I think you might need higher voltage and lower quiescent current.
Hello Giuseppe! Thanks for Your jobe)
Can You add 6BX7, 6AH4 and 6CK4 tubes in yours fantastic collection?
Best regards, Dmitry.
Added to my todo list.
Thanks
6BX7 is finally available 🙂
Thank You very much!
6AH4 and 6CK4 ready as well
Fantastic)
Many thanks!
Hello Giuseppe! Thanks for Your job !!!!!
6E5P , 6E6P , 7721 or D3A ?
Hi,
Addedd to my long pending list
D3A is now available. I did not find enough data in datasheets to find parameters for 6E5P , 6E6P , 7721: I need either penthode mode grahs with various G2 or pentode mode with one G2 and a triode mode graphs
Thanks you.. and Could be that when i look E180F in triode mode , dont run correctly.. For example, i put 200v y then figure 100v or 150 !! and the current too is diferent to i put.. Santiago.
Hi,
I was not able to reproduce the problem. Can you send me a screeshot?
However, note that Vq and Iq cannot be chosen arbitrarily. They depend one fron the other and the operating point MUST stay on the loadline.
Giuseppe , i was in Load Resisitve , not reactive.
it was my mistake
Ok! Perfect!
Hello Giuseppe, Thank you so much for your excellent work. I notice when a certain tube is selected, the calculator starts up with defaults to a certain V+ and Iq. Are these the optimum operating conditions you or the data sheets suggest ?
Hi Joseph,
Default values are, in most cases, taken directly from datasheets. Optimal values depend on specific design and preferences.
Thank you, Giuseppe
Thank you Guiseppe for a great tool and generous contribution of time.
I know you have a long to do list, but could you add the sub-miniatures 6021 and 6111?
Hi,
Sorry for my late reply. They are now in my pending list
6111 and 6021 are now available
Hey Giuseppe,
Hopefully you’re doing well.
I was wondering if it would be possible to calculate the gain from the load-lines as well?
Hi,
Sorry for my late reply. Yes it is possible. I add it to wished features.
Excellent work!! Could you add the EL36 in UL mode?
Added to my pending list
Hi,
El36 is available at last
Dear friends,
Sorry for not being reactive during last months.
The lockdown, and the consequent “work from home”, absorbed me and I did not have enough time to dedicate to hobbies.
When you are in office, the moment you lock the door and return home makes a clear distinction between your job and family/hobbies/entertainment time.
Doing office work from home makes this distinction fuzzy and you end up dedicating less time to hobbies and entertainment.
Hope next months to be able to dedicate more time to this
Hello Giuseppe!
Thanks for Your’great book. Could you add the 6H2P, 6C3P-EB, 6H6P?
Thank you verymuch.
Hi,
6H6P (6N6P) is already available.
I addedd the others to my todo list.
Giuseppe
6N2P, 6S3P-EV, and 6N6P are all available now.
This tool shows promise!
A couple of questions..
-Is V+ meant to be the power supply (from the rail) or the plate voltage (after DC voltage drop across the OPTs primary)?
-Does this tool support cathode biased implementations or just fixed bias?
Thank you
Hi,
V+ is power supply.
Grid voltage, in real circuis can be obtained using fixed or cathode bias. However, from the anode characteristics graphs point of view there is no difference.
I am planning to add computation of the cathode resistor in future releases. This is already available for the power stage loadline calculator.
Buongiorno!! Can you add 6021 Miniature tube? Grazie Tanto!!
E anche 8417?
Added to my pending list
6021 ready!
8417 available as well
Fantastico Giuseppe!! Veramente bello. Per chi come me si appassiona a ricavare il massimo da apparecchi vintage, sarebbe bello se ci fosse la 7591, anche se e’ fuori produzione. In ogni caso, grazie! E complimenti.
Giovanni
7591 added to my pending list
7591 is now available
7591 ready!
Hello Giuseppe
Thank you for investing the time into the calculator and making it available to us.
Is the 13E1 tube going to be added at one stage?
Cheers
Stephan
Added to my pending list
5902 possible? thanks for your hard work. how can i donate?
Added to my pending list.
I did not start with a donation program. However, the ebook version of my book is available at a very reasonable price 😉
also second the 6111 6021 suggestion
added to my pending list
6111 and 6021 are now available
Hello, can PX4 be added? This is great for for visualisation.
Hi,
Added to my pending list
PX4 is ready to be used
Thank you for the effort you have put in. Please could you add 6S4A .
Added to my pending list
6S4A is now ready!
Hi Giuseppe,
Hopefully you’re doing well!
Your little calculator is still highly appreciated!!
I came across two interesting tubes, ECL113 and ECL81.
I think they are actually very similar(identical)?
Thanks as always!
Hi,
Everything is fine here! Hope the same to you.
ECL113 and ECL81 are now in my pending list.
Ciao Giuseppe! This is brilliant. If you want some ideas for the pending list, let me suggest ECC82, EF80, EF184 and JJ’s ECC99.
Cheers,
Andy
Thanks!
addedd to my long pending list 🙂
Hi Giuseppe,
Any plans to add TS 7581 to your calulator?
I added it to my loooonnnng pending list .-)
Ecc99 is now available in the calculator
ECC82 is available!
EF80 ready as well
7868/EL506 just added as well
Hi Giuseppe, this tool is awesome! I love the wide range of tubes you cover. There are valves here that you just won’t find on another calculator. Would it be possible to add 6AT6/6AV6 tubes to the list?
6AT6/6AV6 are now in my pending list. Be patient 🙂
Ciao Giuseppe,
it would be really nice and useful if you add a feature: parallelize the tubes.
Do you think it is easy to be done?
Hi,
yes it is not difficult.
However, you can already simulate parallel tubes if you just use double load values.
Ciao Giuseppe, great tool! May I ask what you use as condition for max g1? Is it g1=0 or the “knee” of the output characteristics? Grazie in anticipo.
Hi Emmanuel,
Not sure I understand correctly. I guess you mean how do I compute power for max g1, right? What I consider max g1 is the max g1 used in the corresponding tube datasheet, which is the maximum g1 I display (not necessarily 0).
Understood! Grazie mille!
Prego! 🙂
Ho Great work, maybe very useful to consider multiple parallel device. Bravo
Hi Angelo,
As I said in other posts, you can simulate parallel tubes by simply doubling the specified load value.
Thanls for this. I can’t select push-pull for 6ak6.
Hi,
in order to use push pull you have to selcet reactive load. Did you try that?
Very nice tool and it looks as if it is quiet accurate. It would be great to have the grid lines labeled and if it would be possible to adapt the voltage and current scaling.
Thanks,
I add these features to the my whish list.
Please add 6C45P
Added to my pending very long pending list
Great job, Giuseppe!
Could you please add 5879? It’s a nice pentode for audio applications.
It is in my pending list. Be patient 🙂
Very usefull. thankyou.
Thanks a lot! Much appreciated!
Hi Guiseppe. I’m a total noob in building tube amps. And I don not understand what your Output Power numbers mean. For instance for KT120: at class A/A2:48.99 at headroom:5.76. How much power I’ll get from an output transformer? On the one hand, headroom power for me means a variable part of a current (which is a signal). On the other hand KT120 is a tube that is capable to generate up to 70W of power into a loudspeaker…
I’m confused.
Thanks.
Hi,
I think I do not undesrtand your question. Can you post all parameters of your simulation (V+, operating point, load, operating mode etc.).
Thanks
I think I understand. Numbers in the power section mean how much a tube works in A or AB classes. This is why I saw about 48 W of a heat, and only 6 W into a loudspeaker.
Thank you very much for a great tool you’ve made for all of us!
Thanks
Giuseppe, I am missing the possibility to connect to tubes same type in parallel.
This, to see if the max allowable plate dissipation can be compensated by parallel connection.
Hi,
when two tubes are connected in parallel, they basically see twice the load. So, you can simulate two parallel tubes by indicating a load twice the real load. Or viceversa, the real load that you use in your build, when you have two parallel tubes, is half the load specified in the calculator.
Great stuff…but could you check the curves of the 211 please ? Your 211 curves show e.g. 112mA @400V while in reality it is 80mA etc…they are quiet different from the data sheet
Hi,
I used this datasheet as a reference: https://frank.pocnet.net/sheets/049/2/211.pdf
And it looks overall quite accurate.
However, I adjusted a bit the graph for values in the area you mentioned.
5687 please
It is now in my pending list
5687 is now available!
Any chance you could add the EL509/6KG6? Thanks.
They are now in my pending list
The 6AK6 model will not let you go in P-P and in SE the B+ is given as 330V rather than the chart which gives it at 180V (which is datasheet value)
Hi,
in order to go in PP you should specify reactive load.
After that, you can set 180V as B+.
In resistive mode, V+ corresponds to the voltage applied to the load, which from 330V is reduced to 180 at the anode.
Would it be possible to add GE5654, 6AK5, 6ж1П, 6BC5, EF40, EF95 tubes to the list? Thank you Rudo.
They are now in my pending list
Great Job! Very very useful!
Thank you
Hello Giuseppe, from Finland.
Your work is very valuable, thank you.
F2a audio tube mihgt be an intersting to add, not for only me but for more commonly. I have realized several amps with those with good success.
Best regards, Mauri
Thanks!
F2a is now in my pending list
Great stuff, but I guess I need some more advise on PSE…if I just double the primary load as you suggested…well…how do I get the correct power and distortion figures ?
One more: Could Ou as well integrate the 813 in triode and the 814 in triode ? I can send you links for the curves if you dont find them, but Andrea (Audiodesignguide) has the 813 and Bartola the 814…
Thanks so much for your great work !!,
If you use two parallel tubes and, in the calculator, you set a load value twice the real load you are using, then power delivered by the two tubes will be twice than the one computed by the calculator as well. In fact you will have twice current at the same voltage.
THD should remain invaried. So, resuming, twice power at practically the same THD.
I also added 813 and 814 to my vert very long pending list. If you have the datasheets I spare some time to search for them. 🙂
My pleasure:
https://frank.pocnet.net/sheets/079/8/813.pdf
https://frank.pocnet.net/sheets/049/8/814.pdf
And the curves as triodes (which is the most interesting part and what I would like to use with your calculator):
813:
http://www.audiodesignguide.com/Claudio845/813triodeAmpl10k_24w.gif
814:
https://i0.wp.com/www.bartola.co.uk/valves/wp-content/uploads/2014/05/814-SE-class-A1.png
Thanks so much !!!
All the best
Thank you!
Hi from China
Really perfect job. Your explanation here is perfect also
One question about two tubes. 5787, 12B4 also. Are they in your pending list?
Thanks a lot
Nikos
Hi,
Thanks!
12B4 is already in my pending list.
I now added 5787 to it.
Be patient: my pending list is veeeery long
i’m sorry my mistake is not 5787. sorry 5687 is the correct tube number. i typed wrong
Nikos
Right! Corrected.
5687 is already in pending list (just some in front of it) 🙂
5687 is now available!
Hi. Please add EC360.
Added to my pending list
Does the V+ on the load line calculator represent the voltage at the plate or the plate to cathode voltage. Thank you
It is the power supply, before the load.
I think that still doesn’t completely answer the question?
Usually the anode (plate)-cathode voltage is given.
Or in other words, the supply voltage WITHOUT the bias voltage (when self bias is being used)
The plate-cathode voltage is the horizontal axis of the graph. V+ is the voltage given to the load. In case of reactive load, V+ corresponds to the quiescent plate-cathode voltage (the red spot corresponding to the operating point). With a resistive load, quiescent plate-cathode voltage is lower than V+, since voltage drops through the load.
In addition, note that the anode characteristic graph and the loadline are drown considering fixed bias (not self-bias).
Devo dire che è molto interessante il suo lavoro soprattutto per me che sono alle prime armi, interessanti anche le risposte alle domande che mi hanno ulteriormente chiarito le idee. posso esprimere il desiderio di vedere anche le curve del tubo 6P21S. Grazie per il lavoro che svolge.
Saluti Sergio
It is in my pending list. Be patient 🙂
Very usefull. thankyou.
Could you please add 6cl6
It is in my pending list. Be patient 🙂
Just discovered this gem. I also thank you for your work.
What’s the possibility of adding 6GT5?
Hi,
Thanks. To many requests 🙂
It is now in my pendilng list: be patient!
Hi, thank you for this fantastic tool. I have a couple of requests if you have time for them: EF184, EF80 and the 5672. Cheers again!
Hi I added them to my pending list.
Thanks
Wow, very nice info and excellent response from you Giuseppe. I found this site by searching for quiescent bias current answers. I’ve come across a formula in a piece written by C.R. Couch. In it he gives a formula Iq = Imax / p but no where does “p” get defined, would you by chance know this?
Hi,
Not sure I can help: do you have a link to this, to better undestand?
Thank you for this tool. Could you please add C3m tube.
Best regards
Added to my pending list
Could you add 6J6? Thank you.
I have it in my pending list …
Could you add 6J6? Thank you.
I have it in my pending list
Hi Guiseppe,
thanks for the great work, especially covering lots of russian tubes I use regularly 🙂
It’s really usefull to quickly get a first idea (within the borders of an idealized model ;-)) about operating points, voltages and load impedances. Can you add a model for the 6P1P-EV please? It’s a “near relative” of EL90 and 6AQ5 but not exactly the same, so this would be appreciated…
I’m looking forward to read your book I`ve just ordered – I can give you a sound feedback if you’re interested 😉
Hi Martin,
Thanks a lot!
I add it to my pending list. Hope to be able to add soon.
6P1P-EV ready to be used!
Thank You, works fine and matches my measurements quite good 🙂
Thank you 🙂
Fantastic job, much appreciated!
I hope you’ll keep up the good work for a long time.
My request would be the king of double triodes, the E80CC.
Added to my pending list … however too many in the list and too little time 🙁
Great, as soon as my daughter gave me the Kindle book from Amazon, I started reading it, it is very comprehensive and detailed. I am waiting when you can add PL504, it is very good for initial tests for me.
Added to the looong pending list
Hello Giuseppe!!! Any chance you can add EC86 and E280F? Also PX40 in the power tube section. 🙂 Thanks, Jeff
Added PX40 in the meanwhile. EC86 and E280F are in my long pending list!
Molte grazie!!! This is awesome!
Awesome Tool Giuseppe!
I’m a bit confused by Iq. Could you elaborate from which part of the tube data sheets this default gets populated? It is plate/anode current or grid current?
Thanks!
It is the anode quiescent current. My model does NOT consider grid current.
Thanks 🙂
Very useful calculators… Any plans for SRPP calculator ( for triodes and penthodes ) ?
Tx
It might be an interesting add… hope to find some time to work on it. 🙂
This is a great tool, really nice work! One can now see dynamically what happens when various parameters change. Thank you Giuseppe!
Thank you 🙂
Hi again Giuseppe,
I think you have mixed the 6550 and KT88 Anode Dissipation values, according to JJ’s datasheets the 6550 should have 35W and the KT88 42W.
I used design maximum power for Kt88, which is 35. 42 is the absolute maximum. See http://www.r-type.org/pdfs/kt88.pdf
While here is 6550 (which can be improved in my model): https://shop.ehx.com/catalog/addimages/6550-tung-sol.pdf
I see, so strange…
Here are the datasheets from JJ:
https://www.jj-electronic.com/en/6550
https://www.jj-electronic.com/en/kt88
In the meanwhile I slightly improved the model for the 6550
This tool is so helpful.
Do you have any info on the new KT170 tube from New Sensor / Tung Sol?
I am starting an amp build using that tube, and would love to see it added when you have the time.
Thanks, and have a great day.
Hi,
I do not have enough data to generate a model. I would need pentode mode graphs with at least two different screen voltages or a grapg in triode mode. Available datasheet only have pentode mode with one single screen voltage 🙁
Hi,
Thanks a lot for for making this webpage. The information you put here and the calculator are amazing.
I have one question to pose to you regarding the calculator, if you don’t mind:
When designing a class AB amplifier, the load seen by the each tube is 1/4 of the impedance of the primary of the transformer for class B and 1/2 for class A.
So, when I enter the value of the “reactive load”, is that 1/4 or 1/2 of the transformer’s impedance?
In my case, I have an impedance of 16kΩ, so should I enter 4kΩ or 8kΩ?
Thanks a lot.
Best regards,
Pedro
Hi,
In Push-pull mode you have to enter the plate to plate impedance. Which, in your case is 16k ohms.