A stable all-normal-dispersion dissipative-soliton mode-locked laser is demonstrated with a Yb3+-doped large-mode-area double-clad gain fiber, and nonlinear polarization evolution and spectral filtering composed of a grating and an aperture are exploited to produce sufficient amplitude modulation to shape pulses of this laser. The laser generates chirped pulses at a 76.6 MHz repetition rate, with an average power of 6.3 W, and a single pulse energy of 82 nJ. Pulse duration of the direct output pulse is 1.33 ps and it can be dechirped to 377 fs after externally compressed. By adjusting the grating, the central wavelength of the output pulses can also be tuned from 1025 nm to 1078 nm.