Just wondering what the two .1 uf capacitors separated by 1 meg ohm resister is doing. The v7 tube is a halfwave rectifier. Im also wondering why they would use a half wave rectifier.
I dont actually think it's as the title says "snubber" but it was an easy title and google had mentioned it as a snubbed circuit.

 

The two capacitors and resistor are a pi filter to give a smooth DC from the rectified pulses.

They use a half-wave rectifier since the AC is just a series of basically unipolar pulses from a flyback type converter and a full-wave rectifier would not add anything to the output.