Once again, no driver stage bypass capacitors are used, as once again we do not want to lower the output impedance of the driver.
      Notice that voltage swings look much like those in the output stage as amplifier example we just covered, the difference being how those voltage swings were created. In our first example, the bootstrapping added voltage swing to the top triode's input. Both tubes actually see the same small driver voltage swing, but the top tube's is magnified. In this example, the bootstrapping subtracts from the bottom triode's input. Both tubes also see the same small driver voltage swing, but the bottom tube's is reduced. Thus, because the voltage swing needed to drive the output stage is so great, and because we cannot rely on positive bootstrapping to artificially create the voltage swing, multiple gain stages are certainly necessary.

    The circuit below shows the output stage configured as a cathode follower, i.e. no gain, low output impedance, low distortion. Once again, each tube sees the same cathode-to-grid signal; but referenced from ground, the signal going into the top triode is much larger than that going to the bottom triode. This time, however, we must create the required gain the hard way. The capacitor that bridges the bottom triode's plate to its driver tube's choke provides a form of negative bootstrapping, as we need to subtract the plate's voltage swing from the driver stage's voltage swing. If a pulse is reflected back into the output transformer's primary, both tubes will work equally to buck it. The triode's input is ground referenced, so it will naturally buck this pulse. The bottom triode will see the pulse (inverted) at its grid, which will also cause this tube to buck the pulse equally.

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