Abstract: A power transformer with internal differential mode distortion cancellation, comprising a primary coil for connection to a power source providing a fundamental frequency power signal, a secondary coil for connection to an electrical load, a magnetic core intermediate the primary coil and secondary coil for providing mutual magnetic couplings of signals therebetween, a further coil connected with opposite phase to one of either the primary coil and the secondary coil, and a high-pass filter connected in series with the further coil for attenuating said fundamental frequency power signal while passing high frequency distortion signals substantially unattenuated, whereby the high frequency distortion signals are canceled in the magnetic core.