The invention provides an apparatus and method of switching more than one bias voltage within an electron beam tube in order to achieve electron beam cutoff. The invention is particularly useful for high-perveance electron tubes in which a large change in focus-electrode-to-cathode or anode-cathode voltage might otherwise be needed to achieve cutoff. In one embodiment of the invention, the cathode and anode bias voltages are both switched by magnitudes well within the capabilities of standard high-voltage switches to achieve beam cutoff.