An improved filter assembly module comprising an open-ended cylindrical housing containing a spindle chassis with a base radially centering the chassis in the housing. Three spindle, rods extending from the base and three sets of three cylindrical spool-wound capacitors are spindle-mounted one set on each rod. A position stabilizer mounted on the upper ends of spindle rods makes stabilizing contact with the housing inner wall. An inductance coil and core is held beneath the base by a plurality of short rods protruding from the base and by a retainer snap-fastened on the rod ends. A housing bottom cover encloses the inductance coil, short rods and retainer, and a cap closes the housing top end. Electrical circuit connectors electrically couple the capacitors, inductance coil and ground and provide output signal leads for coupling to an associated meter or the like. The housing interior space, cover, cap, capacitors, inductance coil, position stabilizer and coil retainer are all totally immersed and engulfed in a solidified thermosetting dielectric insulation material cast in-situ in the housing, cover and cap.