Boss Audio MR800 User Manual in English - Page 7

6. Connect all line inputs and outputs (if used) using high-quality cables. Connect all speakers, following the diagrams in this manual. Be sure to observe proper polarity to avoid audio phase problems. 7. Insert fuse(s) into the battery fuse holder(s). 8. Recheck all connections before powering up the amplifier. 9. Set all level controls to minimum position, and set all crossover controls/switches to the desired frequency points. 10. Power up the head unit and the amplifier. Then set the volume control on the head unit to about 3/4 volume, and adjust the amplifier's input level control(s) to just below the level of distortion. 11. Further fine tuning of the various controls may be necessary to obtain best results. Don't misuse the level control! Do not mistake the input level control for a volume control! It is designed ONLY to match the output level of your audio source to the input level of your amplifier. Do not adjust this input level to maximum unless your input level requires it. Ignoring these instructions will result in an input overload to the amplifier, and excessive audio distortion. It can also cause the protection circuit to engage. Marine MOSFET Amplifier User's Manual - page 7