[EdHolland]

I think what Mike is trying to say is that the extra winding (presumed for power supply choke) is not really part of the audio circuit, because it is decoupled by the large electrolytic. In some audio designs, transformer taps are used to provide feed-back of the audio signal, either to the input of the output tube, or to an earlier stage in the audio chain.

In this case, it is a good thing that your radio doesn't have that design. You will be able to use a substitute transformer that does not feature the extra winding. BUT it will require a slight rearrangement of the power supply. The wire that was connected between the extra tap and the 50 mF electrolytic (C3) could, for example be connected to the main B+ through a suitable series resistor to get the correct voltages shown on the RF tubes. Alternatively, a small choke could be used, but the choice of value would be guesswork.