[Arran]

Mike;
The second version, the ones with the single ended #47 power outputs, had AVC/AGC, whereas the one with the P+P #45s did not and required the local distance switch on the rear apron. Why they could not have added a local distance switch in conjunction with the
power switch may be lost to history.
On the other hand Philco would frequently carry over models from year to year with no changes other then the date code, but with others there would be no less then six different circuits used for the same set, the worst examples being some of the post war models, like the 46-1201 Bing Crosby. I have a Canadian "Hippo" model that has a TRF amplifier stage, but two others use the extra IF amp and that used the XXD/14AF7, I will have to see which version is the better performer. I think Philco designed sets around whatever tubes, or speakers, they either could buy in volume, cheap, or what was immediately available.
Regards
Arran