A pickup sensor is disclosed for a magnetostrictive sensing instrument for sensing position of a magnetic field. The instrument includes an elongate tube having a near end and a distal end. A magnetostrictive wire in the tube has first and second ends. The second end is operatively secured at the tube distal end. The pickup sensor comprises a housing mounted proximate the tube near end. A pair of crystals are in the housing sandwiching the magnetostrictive wire so that interaction between an electric pulse on the magnetostrictive wire and a magnetic field produces a torsional wave on the magnetostrictive wire sensed by the pair of crystals. A pair of spring elements are mounted in the housing sandwiching the crystals to provide consistent contact force between the crystals and the magnetostrictive wire.