Power Tube Load Line Analysis

[RoadShow]

Yesterday I was reading up on Push-Pull Output Power Stage at Merlin’s website:
https://www.valvewizard.co.uk/pp.html
and I decided I wanted to make some graphs for a couple of my builds: my Hoffman AB763 single input and Mojotone’s JTM45.  However, what I came up with by copying the graphs out of data sheets and generating load lines for the applications using 6L6GC and EL34 and following the same approach put the load lines on the “wrong” side of the power curve.  (see attached)

So, I went to Giuseppe Amato’s website
https://www.vtadiy.com/loadline-calculators/power-stage-calculator/#calculator
and used his load line calculator and it generated pretty much the same results.

Can someone help explain this to me and set me straight?  Am I doing something wrong or interpreting it wrong?  I was hoping to see a plot similar to what Merlin had on his website.

Thanks…

[Merlin]

To quote myself: "This load line may cross the max dissipation curve over a portion of its length- this is allowable."
As long as the bias point is comfortably below the max dissipation curve, the *average* power will remain safe, even though the *peak* power crosses the line.

[RoadShow]

To quote myself: "This load line may cross the max dissipation curve over a portion of its length- this is allowable."
As long as the bias point is comfortably below the max dissipation curve, the *average* power will remain safe, even though the *peak* power crosses the line.

Thanks, I saw that first comment, it just looked to me as though the load line crossed over a significant chunk of the curve.
I can see the logic in the second comment, and the bias is comfortably below, and will hopefully file that away to memory and not forget it in a year or two 

[pdf64]

Can someone help explain this to me and set me straight?  Am I doing something wrong or interpreting it wrong?  I was hoping to see a plot similar to what Merlin had on his website.

Thanks…

Idle conditions only apply at idle, 0 signal. When the amp's putting out power and the output valves are drawing more current, there's no way those HT and screen grid voltages will hold up there, especially so with EL34 screen grids.