A push pull amplifier is a special type of arrangement used in class B amplifiers where the active device pair push (supply) current and pull (absorb) current from load. Push pull amplifiers are more efficient than the single ended power amplifiers. Because of the symmetric construction of two sides of the amplifier the even harmonics are cancelled and output signal distortion can be minimized. Another advantage of the push pull amplifier is the effect of ripple voltage that may be contained in the power supply is balanced out. The main disadvantages of the push pull amplifier are the need for two identical transistors and the requirement of bulky and costly coupling transformers used for phase splitting.