Super legato linear system This unit employs super legato linear system which drives low impedance speakers and assures powerful reproduction without low crossover distortion and switching distortion over the wide range. Spontaneous twin drive power supply circuit Condensers having large capacity are used for the voltage amplification drive stage of class A and power output stage of class B. Thus, a stable output and high quality sound are obtained, resulting in exclusion of power interferences. The class A stage realizes a stable operation free from interference of the power stage even when an instantaneous or strong output is received. G chassis A one-piece, hard chassis, named “Gibraltar”, reduces distortion caused by vibrations. This reduces air vibrations from the floor and speakers and also reduces vibrations caused by the power transformer and power transistors.