A connector assembly includes a conductive collet spring with an annular base and integral circumferentially spaced cantilevered generally parallel arms terminating at tip members diametrically spaced closer than the diameter of the base. A conductive housing overlying and electrically and mechanically engaged with the collet spring engageably receives the electrical terminal of a medical stimulating device and includes a distal mounting flange. A non-conductive barrel is fittingly attached to the distal mounting flange of the housing and has an inner bore for receiving a medical electrical lead. A non-conductive header encapsulates the connector assembly, is mounted on the casing, and has a header bore aligned with the inner bore for receiving the medical electrical lead which, when inserted and sufficiently advanced through the header bore, the inner bore, and the annular base, the tip members firmly engage the proximal terminal pin thereof.