This paper describes a high-speed, robust, scalable, and low-cost feed-forward time amplifier that uses phase detectors and variable delay lines. The amplifier works by detecting the time difference between two rising input edges with a phase detector and adjusting the delay of the variable delay line accordingly. A test chip was designed and fabricated in 65nm CMOS. The measured resulting performance indicates that it is possible to amplify time difference while maintaining high-speed operation.