That was my understanding also Etor. Since the output circuitry is duplicated for balanced signal, one could use just a single pair of tubes for rca output.
Output from the dac is 5v / 22 ohm, so there should be no shortage of drive. It might be the case that Berning uses interstage traffo coupling which caused the sound to become overly damped with the TVC however I am quite comfortable with the caveat I made earlier. Autoformer may give a better...