Amplifying devices where the gain is automatically controlled by the level of the input signal performs dynamics processing. Non-linear components simulating tube amplifiers can be used in these devices to make musical signal audibly dense [1]. This paper deals with the simulation of tube amplifiers using the power polynomial approximation of transfer characteristic and their use in dynamic range controllers. The influence of various non-linear amplifying devices simulating tube amplifiers on the output signal spectrum of dynamic effects is presented as well.