ABSTRACT
This chapter deals with the specialised circuit blocks that make up mixing consoles. Most mixer channels have both microphone and line inputs. On the lower-cost consoles these are usually switched to a single amplifier with a wide gain range, the line input being attenuated to a suitable level first. Mixer input channels have more or less sophisticated tone controls to modify the frequency response, either to correct imperfections or produce specific effects. In a group module, an inverting insert send amplifier is often used to correct the phase inversion introduced by the summing amplifier. In more complex consoles, a direct out is available from each channel. This is a postfade signal, which can be fed directly to a recording device without sending it through the routing and summing systems. Most of the circuit blocks used in group modules carry out the same functions as they do in the input channel modules.
