This mic pair is based on the ELAM251 circuit, but instead of the edge-terminated C12 style capsule, these use center-terminated U47 style capsules.
The circuit is built with turrets on Plexi glass boards. The sensitivity of the capsule leads can be either floated or built on a high impedance board, like Plexi glass.
Because these mics use a cap bypassed cathode resistor and the heater current is not used in the audio side of the circuit (like it is in the U47), the required power supply is simpler.
These mics use a 6072 tube, which is a low noise version of the 12AY7.
A 10:1 Beyerdynamic transformer is used in reverse from the tube plate, blocked with a 1uF film capacitor.