The EAR 822Q Pultec type equalizer has been designed to be highly flexible and thus useful in a wide range of applications. Passive equalization networks combined with valve input and output buffers are used in order to minimize disturbing side effects such as phase shift and ringing. The audio circuitry conforms to the EAR principles of simplicity and subjective "transparency", with low distortion at all normal signal levels. A "clickless" bypass switch allows easy comparison between the processed and direct paths. Variations in response include low pass, high pass, band pass and high or low frequency shelf with variable Q and turnover frequency. The EAR 823MQ is a variant of the 882Q designed for use in the midband. It is slightly simpler, with the frequencies set closer together in order to give more precise control over this critical spectrum.