JBL Model 5306 Mixer/Preamplifier The JBL 5306 is a solid-state mixer/preamplifier capable of integrating two program channels and six microphone inputs. It features operator-oriented controls, exceptionally wide dynamic range, extended frequency response, low noise, and minimal intermodulation distortion. Each of the six microphone channels is equipped with an overdrive indicator that flashes when its preamplifier circuit begins to overload. In use, the indicator becomes operative before distortion reaches audible levels, providing ample warning to make the proper gain adjustment. The unusual dynamic range of the 5306 results from a preamplifier circuit whose operational characteristics are changed as the gain control is adjusted. Reducing the voltage gain of the circuit permits greater input without clipping the output signal. Since the Master Gain controls the mixing circuit in a similar manner, the 5306 is particularly well-equipped to handle extreme loudness variations.