$7.00
Designed by Matador, this booster PCB is a small SMPS adder board that could be tacked on to existing phantom-powered mike designs to provide a full +60V polarization supply. The intention is for this to be usable in U87 clone designs to convert them to near "U87AI" specifications, but there's nothing preventing them from being used in other designs that lack a full +60V supply as well.
The original U87 circuit utilizes heavily filtered phantom for polarization voltage and the "AI" uses a switch-mode power supply (SMPS) design to boost the +48V phantom voltage to a more optimal +60V polarization supply. The intention for this board is to convert currently available U87 clone designs to near "U87AI" specifications, but there's nothing preventing these small-footprint add-on PCB's from being used in other designs that lack a full +60V supply.
The design is based around an LM5002 SMPS chip with an integrated boost transistor. This chip is good to over an amp, however given polarization supply really have no DC current requirements, the specs of the external parts can be greatly simplified. This design features an input RC filter and an output LC filter to keep it both quiet as well as prevent disturbances of the circuit providing the power to the board.
The official build and support thread for this project with all BOM, schematics, and support documentation can be found here.