We report on a new technique which allows electro-optic sampling to be performed in a frequency range which is above the 1/f noise regime of the pump-probe laser, while at the same time utilizing the high-sensitivity, low-noise properties of an audio-frequency lock-in amplifier. This new approach to electro-optic signal extraction has resulted in an unprecedented improvement of two orders of magnitude in signal-to-noise capability. The new technique is compared to previous, conventional approaches.