A system for heating a site in a patients body includes a transformer having a primary winding and a secondary winding, the secondary winding having at least one center tap to provide a patient reference and at least two sources of radio frequency (RF) energy, the two sources of RF energy being out of phase with each other. A group of electrodes is connected to the sources of RF energy provided by the secondary winding to be simultaneously energized. The arrangement is such that there are more active electrodes connected to one of the sources of RF energy than another of the sources of RF energy with the energy supplied to one active electrode being out of phase with the energy supplied to an adjacent active electrode.
