Design of a compact regenerative laser amplifier based on two Yb:YAG thin-disks is presented. Energy up to 100 mJ in picoseconds pulses will be delivered with a repetition rate of 1 kHz. System is designed for seeding a kW-class multipass amplifier for industrial and scientific applications. Laser heads are pumped at zero-phonon line (968.825 nm ) by stabilized high-power pump diodes operated in pulsed regime. Seed pulses are produced in a fiber oscillator at 1030 nm and CPA technique utilizing transmission gratings for pulse stretching and compression is applied.