Recently, Mamyshev oscillators (MO) have attained a lot of attention, due to their generation of mode-locked pulses with outstanding output parameters in terms of output energy, spectral bandwidth and pulse duration. We present a MO with output pulse energies in the range of 0.5µJ, an optical spectrum ranging from 1010nm to 1060nm and an externally compressed autocorrelation duration of less than 100fs. This MO completely consists of commercially available standard step-index fibers. In order to handle the high pulse energies, we apply a few-mode gain fiber with a core-diameter of 20µm in the second arm of the oscillator.