Switching power supply for speaker

The utility model discloses a switching power supply special for a speaker. The switching power supply comprises an alternating current power supply, an internal resistance adjustment circuit, a rectification filter circuit, an oscillation driving circuit, a transformer and a rectification filter output circuit, wherein the internal resistance adjustment circuit is connected in series with the alternating current power supply, and is supplied with power by the alternating current power supply; the rectification filter circuit is connected in series with the internal resistance adjustment circuit, and is used for increasing the internal resistance of an alternating current loop; the oscillation driving circuit controls current flowing through a coil of the transformer by regulating the on and off of a triode; the transformer is used for voltage transformation; and the rectification filter output circuit converts alternating current into direct current, and outputs the direct current. The switching power supply