A new-type shock wave generator is designed for an electrohydraulic lithotriptor. The generator consists of a reflector and two electrodes. The performance of the new generator is evaluated at different voltage settings, and is compared with that for the old-type generator from the LiteMed Inc. The generator performance is measured based on the average of the peak pressures for every 500 shocks. The in vitro study suggests a better voltage setting of 6-8 kV for the new-type generator, since the new-type generator can produce higher peak pressures and more consistent-energy shocks at lower voltage than the old-type generator does.