Positive Filter on Alternator

Among the more complicated technical issues are the annoying buzzes and various interferences caused by the car's electrical devices and reproduced by the onboard audio system, especially if it is a powerful system that involves the use of amplifiers. The interferences from the car's electrical system are always circulating and cannot be eliminated but only grounded: based on this premise, it is clear that the first precaution is to ensure that all electronics of the system are properly grounded, ensuring good contact with the chassis by stripping the mounting point. Regarding the positive power supply, it is recommended to take it from the battery, inserting a fuse to protect the cable itself, using a shielded cable and possibly adding a filter. To further improve the situation, it is also suggested to replace the cable that runs from the alternator to the battery positive, always using a shielded cable and a filter. It is important to remember that amplifiers must also receive the positive from a suitably sized cable connected to the battery; absolutely avoid deriving the cable from the fuse box as it is a source of noise and often cannot handle extra loads (unless you are installing a modestly powered amplifier). Buzzing is often caused either by a battery that is on its last legs or by issues related to the grounding of the battery negative. An exhausted battery significantly increases its internal resistance, causing the electronics to 'see' the alternator as the preferred source, resulting in weak filtering action from the battery, making it easy to perceive buzzes that may not have been present before. Another suggestion is to avoid bundling all the cables together and ensure that signal cables are kept away from the car's power and audio system cables: indeed, pre-out extensions, especially those that are unshielded and inexpensive, can pick up electromagnetic interference from the noise present in the car's electrical circuit. The remedy, of course, is to keep the pre-out extension at least 10 cm away from the power cables. The same applies to the section of the pre-out extension that runs through the dashboard, try to keep it away from control units and electrical devices.