Two-tube-feedback pair
     One possible measure of success might be a simple coupling capacitor count, with less being better than more. By this standard, the two-tube-feedback pair would seem a sure loser, with its internal coupling capacitor and its two output coupling capacitors...but then, maybe not.

    Direct coupling between tubes eliminates the internal coupling capacitor and accepting the consequences of retaining the first triode's cathode voltage at the output eliminates the second coupling capacitor.
    In the circuit below, we see a pair of two-tube feedback amplifiers being used in a way that only brings the count of coupling capacitor to three. This arrangement is possible because the second triode's cathode resistor is bypassed (which it would probably be even if the coupling capacitor had been retained), which allows us to specify the resistor's value arbitrarily.

    Why so many coupling capacitors? If we attach the feedback resistor directly to the second triode's plate, the first triode's cathode voltage and the second triode's plate voltage will be thrown off. Using a coupling capacitor between plate and feedback resistor isolates the feedback resistor from the plate, but not from the first triode's cathode, which will impose its DC offset on the resistor; thus the need for the secondary coupling capacitor.

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