The OT-300a is a heavy-duty step-up autoformer accessory that adapts any power amplifier output with a maximum voltage of approximately 17 to 35 volts to drive a 70-volt distributed line with up to 300 watts. Four voltage taps let you choose the one most appropriate for the amplifier. Conversely, the OT-300a can be used as a high-power speaker transformer, driving loudspeakers with up to 300 watts from a 70-volt distributed line.