Noise filter OE LF4A


The presented filter is designed to keep of the typical alternator noise (humming noise that changes with the engine speed) from the audio system.



Because of the many distributed mass points on the chassis of the vehicle on which the various consumers are connected, is obtained due to the associated mass flow, an interference signal which is to measure not only the positive voltage-carrying line, the mass is also contaminated with this disturbance signal . This noise signal whose frequency depends on the speed of the engine, is often found to be very annoying. This disorder can´t be eliminated with conventional filters because of missing an important reference, a trouble-free mass.

The solution:
The filter OE LF4Ais built in quad technology and tailored to the broadband spectrum of the alternator. The applied technique allows the filtering of the mass to the same extent as the positive line.

The filter is preferably build in the power of the audio system and an existing handsfree or on-board electronics. Our filters are equipped with the necessary adapter, which is an effort of a few minutes to build in the filter to the vehicle. To ensure the effectiveness of the filter, it is very important that the audio - system mass also is disconnected from the vehicle. If necessary the audio amplifier has to be srewed with isolated mounts to the vehicle chassis, Because all other Blaupunkt components get their operating voltage from the CPA amplifier. Tests with our customer vehicles give us very postive results.