An experimental ferrite-loaded coaxial line-based pulse-sharpening system for repetitive operation and with output amplitudes of up to 20kV into 50 Ohm is described. Output rise-times are found to reduce with increasing pulse voltage, down to 60ps at 20kV. Principal features of the system are a multi-stage ferrite line design. axial magnetic biasing, and an oil dielectric/insulation layer. This system shows the potential of ferrite line pulse sharpeners for generating 50-100ps rise-time pulses at 10-20kV and upward.