Electronic – Why are the capacitors set up this way in this old tube radio

Safety standards (UL, CE, etc.) place a limit on the amount of leakage current allowed to return on the earth ground. By using the 4 capacitor arrangement, the line-to-line filtering is made independent of the line-to-ground filtering. i.e. you can make the line-to-line capacitors a larger value without increasing the ground leakage current. Then the value of the single capacitor to ground can be set to not exceed the leakage current limit.

Clarification: By leakage I do not mean dielectric leakage. I mean AC current flowing through the capacitor because it is a capacitor. In the three capacitor topology, unless the three capacitors have exactly the same value (unlikely) and the AC line voltages are perfectly balanced relative to ground (unlikely) there will be AC current flowing in the ground wire which must be limited.

It wont work .C4 stops the detector diode from working .Remove C4 by shorting it .R2 is way way to low and will load the tuned circuit meaning no selectivity.Use a high impedence buffer like say a MPF102 or an opamp to keep some selectivity.Your audio output stage looks iffy so recheck the biasing .The Ge diode is slightly better than the Schotty here.