The D37/30 is a mystery and no data can be found. It is an EHT rectifier and looks like the DY802 and similar. However, at 1.4 Volts on the heater it draws one amp not 600 mA and produces no glow. To match the glow from the DY802 heater requires three Volts and takes 1.15 Amps. Clearly designed for a greater cathode current.
The three supports for the anode plus top cap connection.
The central oxide coated cathode with insulated heater. At the top the fixings for the anode supports to the glass can be clearly seen.
The thin glass tube envelope is 22 mm in diameter, and excluding the B9A base pins is 67 mm tall.
Updated March 10, 2018.