Interesting, I guess it is not a fully balanced pre-amplifier.
I afraid I not understand what you mean say by balanced(balanced inputs
??), this model is Stereo, just one power supply(not the SE model).
If I remember well the circuit is the Mu-Follower from the 1950s, it use two tubes only per channel, it had less DHT than the SRPP, I unaware if the Mu-Follower can be done in a balanced circuit, if so it would use 4 tubes per channel.
