what type of tremolo is on a 1972 Silverface Princeton Reverb

To create another model in the line of amps. Plus as power requirements increased models were renamed .The Deluxe tweed started as a 12 watt and eventually went to 22 watts. The Tweed twin started out as 35 watts and went to 135 watts!

The PR is closer to 15W. An amp’s maximum output is determined by the power tubes but more often than not it is limited by the transformer set. A pair of 6V6s can put 30W but most designers do not run them at their maximum. Fender chose to use a transformer set than can only produce 12 to 15W on a PR. This made the amp cheaper to produce and also allowed them to use a lighter speaker. All that said a Deluxe Reverb’s 22W rating is very generous. 17 to 20W is more arcuate.

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?