The ALLEN & HEATH MixWizard WZ20:8:2 is a dedicated 8-track rack mount or desk standing mixer with 8 mono inputs and 6 stereo inputs. All mono input channels have a 4 band 2-sweep EQ with 6 individual aux sends and Direct output. The 6 stereo inputs have a 2 band EQ with 2 stereo cue/aux sends and 2 mono aux sends. The 8 tape return inputs have individual level and pan controls with a stereo cue facility . In addition the MixWizard WZ20:8:2 also has extensive talkback facilities and an internal 1kHz sinewave oscillator for level checking The internal power supply unit is located in the rotating connector module. CONSTRUCTION All metal chassis for 19" rack mount in 10U space. Comprises a 16swg steel front panel housing individual channel circuit assemblies interconnected by means of soldered copper wire busbars. The connectors are housed in a rotating connector module for either rack or desk mounted applications. Access to the channel internal assemblies is by removal of the 18swg folded steel base. Access to the connectors and power supply components is by removal of the rear cover of the connector module without the need to remove the console base. The channel assemblies may be removed for servicing. THE CIRCUIT COMPONENTS The MixWizard WZ 20:8:2 is manufactured using high performance industry standard linear op-amp and discrete semiconductor circuit devices. In particular the switches and potentiometers have proven to be durable and problem free. When operated correctly the normal performance of the unit introduces no noticeable audio signal degradation. AUDIO INPUTS AND OUTPUTS All XLR connector inputs and outputs are balanced (differential) with high impedance inputs and low impedance outputs. To use these with unbalanced equipment the -ve signal should be linked to 0 V in the cable or input connector. All unbalanced connections are line level 3-pole TRS jack sockets. All outputs are low impedance and thus capable of driving several high impedance inputs simultaneously. All inputs and outputs are in phase. THE PFL SYSTEM The console PFL switches send pre-fade signals to the PFL mix bus. These signals are switched with 4053 CMOS gates located on the RIGHT circuit board (PCB No: AG2939). The supply for the 4053 is ± 8 V DC and is derived locally from the ±16V. The gates are switched when a PFL switch is selected.