[Radio Wrangler]

It went something like this..

the triode was a useful valve with some good properties, but against it was the action of the stray capacitance from anode to grid creating feedback and reducing the gain.

So to solve this, someone put a second grid around the first one. This grid was decoupled to chassis so it had no signal on it. We got some g1 to g2 capacitance and anode to g2 capacitance, but very little of the more damaging anode to g1 capacitance.

This was now a much higher gain bottle. But the screen grid had to be biased at a high positive voltage else it reduced the current too much. Then when the anode voltage dipped below the screen voltage, anode current would switch from the anode and flow to the screen grid instead. The screen grid being more positive than the anode had become a much more tempting target for the negatively charged electrons. This made the famous kink. in the anode current at lower anode voltages. The valve was useless for any application needing a wide voltage swing.

So manufacturers sought ways of fixing the kink with various electron ballistics tricks. While the engineers were doing this, the marketing departments were making all sorts of claims, coining trade-names and sowing a lot of disinformation and scuttlebutt about competitors. It is now somewhat uncertain who did what and why. The waters were muddied so much we still get confused by it all. Patents and lawsuit were whizzing around.

David