JJ load lines?

[lowell]

Anyone know how to plot a load line on these JJ spec sheets? It's weird cause they have the plate curves but no grid curves. Not used to that.

[martin manning]

I think it would go like this:

Interpolate along the horizontal axis using the Ua lines to find your supply voltage. Say you're using ECC83, and it's 250V. That is at about -3.4 Ug(V), at zero plate current Ia. Then pick another Ua line, say 150V, and use the anode resistor value to calculate the anode current Ia using Ohm's law: For 100K Ra, and 250-150 = 100V drop, that is 100V/100K = 1 mA. Find the point where the 150V Ua line intersects 1 mA Ia, and that point is on the load line. Looks like you really have to find a point for each Ua line and connect the dots, as the load line doesn't seem to be a line on this plot.

MPM

[lowell]

lame on JJs part, thanks for that though.

[tubeswell]

I got it - their other pre-amp tube datasheets show Vg lines and the ECC832 datasheet tells you to refer to the ECC83 and ECC82 datasheets. How about that then?

[lowell]

alrighty tighty!