Also, there is a LOT more to capacitors than many realize, and far above my knowledge. For example, high power linear RF amplifiers---------there is, has been, and may be many. All the way from "dirty" junk made by pirate CBers to decently designed legal amateur radio amplifiers, and on to really rugged commercial and military equipment.
In the output circuit you must have a cap that will withstand the very high anode voltage of the output tube(s) but at the same time conduct the AC waveform of the RF output in an efficient manner. THIS TASK CAN PROVE TO BE difficult, and depending on the impedances involved, even more so. Some caps can have many of the same "specs" on paper and yet not be able to carry the high RF current necessary for good operation.
