Normally a triode works into a plate resistor, this builds up the plate voltage when current flows. It is normally 100K ohms. The cathode may or may not have a cathode resistor. A cathode resistor also builds up a cathode voltage when current flows. The split load cathodyne phase inverter simply splits the Load in two. Instead of a 100K plate resistor, a 56k or a 47k ohm plate resistor is used along with matching cathode resistor of the same value. The load is splitted between the plate and the cathode. Equal but out of phase signal voltages will appear on the cathode and plate. But how does it work? Look at the circuit: Ground<>cathode resistor<>12ax7<>plate resistor<>ground Now add the signs on the resistors. Ground <> (-cathode resistor+)<>12ax7<>(+plate resistor-)<>ground Note the reversal of the polarity of the resistors and that the cathode resistor will develop its voltage on the right side and the plate resistor will develop its voltage on the left side. When the AC component of the current flows left to right, a positive voltage develops on the cathode and a negative on the plate. Reverse the current direction and now the plate resistor develops a positive voltage while the cathode develops a negative voltage. This is meant to show why the signal voltage on the cathode and plate are equal but in opposite phase.