5 Power amplifiers

5.5 Frequency response

Frequency response is not much of an issue for solid state amplifiers. A typical range is 10 Hz - 100 kHz. However, if not explicitly mentioned in the specifications, this is measured at low power. The curve could change significantly when measuring at full power. This is called "power bandwidth". Low frequencies demand more from the power supply capacitors, since low frequencies draw current for longer periods of time than high frequencies. High frequencies demand more from the electronics' slew rate 5.1 Specifications, since fast changes of the output level are required. Both these limitations result - obviously - in distortion, but even then, a good amplifier will perform its duties over a far greater frequency range than that of the human ear.

Tube amplifiers are a different case altogether. It is the often limited and sometimes even bumpy frequency response that contributes to the sound character of these amplifiers. Together with the other imperfections they make the amplifiers come to life. Quite opposite from a solid state amp, where the design goal usually is to make it sound as clean as possible.

© Joris van den Heuvel 2001-2009