1. Input jack: Connects directly to your instrument. 2. Channel switch: Push and release button to switch between channels 1-4. This button is also used to program when the footswitch is used. Please read the footswitch programming section. 3. Gain control: Each preamp module has a gain control, which can be adjust for the desired amount of gain and distortion. Each module has different levels of gain. 4. Bright switch: Acts as a presence switch, and adds in additional high frequency. Each module has different level of bright adjustment. 5. Bass control: Controls the amount of low frequency for each module, adjust to your desired level. Each module has a different low end frequency response. 6. Middle control: Controls the amount of mid-range frequency for each module, adjust to the desired level. Each module has a different mid-range frequency response. 7. Treble control: Controls the amount of high frequency for each module, adjust to the desired level. Each module has a different high frequency response. 8. Master level: Each module has it own level control. This adjusts the desired amount of volume for each module. Please adjust each module to similar volume level, than use the chassis master to adjust overall volume. 9. Thumbscrews: Each module has two thumbscrews that securely lock in each module. To change modules, simply loosen the two thumbscrews until they feel loose. Carefully slide the module out using the thumbscrews to pull, and slide in a new module. Press in the new module in using the control knobs, until the module is flush with the front panel. Push in the two thumbscrews, and turn to tighten until tight. 10. Effects control: This knob is used when using the parallel effects loop on the rear panel. Hook up your external effects processor in the parallel effects loop, and control the amount of effects with this knob. Turn to dry for no effects, or wet for maximum effects. You