Disclosed are electric cables with improved armor wires used with wellbore devices to analyze geologic formations adjacent a wellbore. The cables include at least one insulated conductor, and one or more armor wires surrounding the insulated conductor. The armor wires include a low density core surrounded by a corrosion resistant alloy clad, where the alloy clad includes such alloys as beryllium-copper based alloys, nickel-chromium based alloys, superaustenitic stainless steel alloys, nickel-cobalt based alloys, nickel-molybdenum-chromium based alloys, and the like. The low density core may be based upon titanium or titanium alloys. The cables of the invention may be any useful electric cable design, including monocables, quadcables, heptacables, quadcables, slickline cables, multiline cables, coaxial cables, or seismic cables.