The borehole source SBS1000 Magnum is designed for P-wave tomography between boreholes up to 1000 m depth.The SBS1000 Magnum consists of three parts housing the complete high-voltage power supply for charging up to about 3 KV. Thesource can be connected to a GO-4 cable head and a standard logging unit (4-conductor cable). The unit is powered from surface by means of a 230 VAC power supply.