The invention relates to a vacuum plasma generator for providing a plasma discharge (10) for treating work pieces (5) by way of a pulsed plasma process in a vacuum chamber (2). Said vacuum plasma generator comprises a generator output (9, 9') having an AC mains supply (6a), an AC/DC mains rectifier system (6) for rectifying the AC mains voltage to a DC voltage, a filter capacitor (6b), a first stage as clocked DC/DC voltage converter (7) with means for adjusting the DC output voltage which produces an intermediate circuit voltage (Uz), comprising a controlled power switch (7a) which feeds the primary winding of a transformer (14) and the secondary winding of which is connected to a rectifier (15) and a downstream intermediate capacitor (12) and configures a floating transformer secondary circuit (23). Said secondary circuit is connected to a downstream second stage which is a pulse output stage (8) and is connected to the generator output (9, 9'). The DC/DC voltage converter (7) has at least two floating transformer secondary circuits (23) and comprises a switch-over device (20) with a switch controller (22) for optionally switching the floating transformer secondary circuits (23) in parallel or in series.