I have searched everywhere I can think of for info on this set. I have found the schematic for a 47M, which appears to be correct, but I cannot find any other info.

What appears to be unique about this set is the extra RF stage (complete with an RF gain control). Otherwise, the circuit seems to be pretty much the same as the 48 and 48B. The case does not resemble either the 46 or 48 series.

One curiousity: The schematic is on the same Rider's page with the "35-late", which I also have. There is NO similarity between the sets--except maybe the year (1935) (The 47M seems to be older than either the 46 or 48 series??)

Some pictures here: http://pixellany.com/PB_47/

A bit more digging reveals that the model 47 traces back to the model 45M. They seem to have similar designs, but the 45M lacks the extra tuned RF stage.

So far, the 47 seems to be the only one in the mid-'30s with that tuned RF front end and RF gain control.