The task of the output stage (or power stage) is to amplify the signal, produced by the preceding stage, to have the necessary power to obtain sound from a speaker. We will consider a power amplifier in Push-Pull configuration, where a pair of vacuum tubes are used simultaneously to amplify phase inverted copies of the same signal. However, before discussing it, we first need to introduce the Single Ended configuration, where a single vacuum tube is used to amplify the signal. The push-pull configuration is then obtained by appropriately pairing two single ended power amplifiers.
