An apparatus for generating signals and energy for transmission to a large mass. The apparatus incorporates a pulsed generator such as a compensated pulsed alternator for storing and for discharging large amounts of energy in a controlled manner for transmission through a vibrator or similar electromechanical device. In the field of seismic exploration, the apparatus discharges seismic source energy into a land mass or water to generate seismic waves which are reflected from the interface between subsurface geologic formations. The pulsed generator permits the seismic source energy to be discharged in a controlled manner to shape the energy signal, and permits large quantities of energy to be discharged to increase the penetration depth and strength of the reflected signals.