Remote versus Sharp Cutoff tubes

Remote cutoff tubes were popular in the tube era. "Normal" or sharp cutoff tubes gave linear gain, and are used in audio circuits. REMOTE cutoff tubes had the advantage of their gain changing with bias. This could be an issue if the output signal covered the full excursion of the power supply, but made AGC (automatic gain circuits) simple, by reducing the gain as the bias became more negative.

No individual semiconductor component can do this. In the solid state era, this same function needed to be done with multi-component circuits, such as Gilbert cell, transconductance amplifiers, and analog multipliers. This is a common theme between the tube and solid state eras.