We report the generation of sub-80 fs pulses with energy in the 100 nJ range at 1050 nm and a repetition rate up to 164 kHz based on a nonlinear fiber amplification system combined with an active control of the spectral phase. This control is performed by an acousto-optic programmable dispersive filter operated at a multiple of its acoustic repetition rate. This result opens up its possible use in highly nonlinear fiber chirped-pulse amplification setups.