The phase inverter of the Princeton Reverb is part of its sound. If you were to use the long-tailed pair of the Deluxe Reverb, it wouldn’t sound like a Princeton, although it would then achieve a higher power output. The Princeton inverter has outputs at its cathode and anode; these are out of phase and are capacitively coupled on to the power tube grids. However, they each can only swing to a peak which is half the plate voltage. To put it another way, the cathodyne inverter, as used in the Princeton, is not as efficient as the long-tailed pair. You would have to increase the plate voltage on the cathodyne phase inverter quite a bit beyond safe operation if your goal was to meet a 22 watt power spec.

When 2 6V6 tubes put into a Deluxe Reverb puts out 22 watts, what limits this amp to only 12 watts with identical power tubes? If Fender put in an output transformer only rated at 12 watts, that’s the same error they made on the 15 watt Tweed Deluxe amps running a pair of 6V6 tubes. Why would they do that?