the amplifier takes the input wave (say 4V) and amplifys it to say 40V. now if your gains are set right, and you put in a nice smooth wave at 4V you get the same nice wave at 40V. notice it wil be the EXACT same wave just bigger. so if you put in a 4V clipped signal you get a 40V clipped signal because again its the EXACT SAME WAVE!