The Top hi-fi amplifier is designed as an amplifier with active frequency crossover networks. With such a system, better acoustic results can be achieved than with passive frequency crossover networks.
The active crossover networks transfer the frequencies which are optimally reproduced by the relevant connected speaker system to an amplifier module (output stage) to which a corresponding speaker (tweeter, mid-range, woofer) is connected.
The hi-fi amplifier is a non-diagnosable control unit. In contrast to the Top hi-fi amplifier, the hi-fi amplifier does not feature a speed-dependent volume boost function to compensate for the noise produced by the vehicle acoustics. This general increase in volume takes place via the radio.
The Top hi-fi amplifier is a control unit in the MOST network. It features the same operating characteristics as the hi-fi amplifier. In addition to the output stages for the tweeters, mid-range speakers and woofers a subwoofer amplifier with two channels is also connected which, in the same way as the Top hi-fi amplifier, controls speed-dependent equalization of the noises attributed to the vehicle acoustics.
The amplifier is connected directly to continuous positive and ground as the power supply. It is activated and deactivated via the MOST bus by the audio system controller. If the amplifier detects a voltage greater than 9 volts at the control input and a voltage which is greater than the voltage at the control input at the continuous positive input, it is activated after approx. 2 seconds.
The amplifier is connected directly to continuous positive and ground as the power supply. The amplifier is switched off if the voltage at the control input drops below the lower operating voltage limit of 9 Volt for a short time (approx. 25 ms).
The amplifier is connected directly to continuous positive and ground as the power supply and operates within a voltage range from 9 Volt to 16 Volt. If the voltage drops below the lower operating voltage limit of 9 Volt for a short time (approx. 25 ms) during the start procedure for instance, the amplifier is switched off and the switch-on procedure is restarted once switch-on conditions have been re-established.
In contrast to the hi-fi amplifier, the Top hi-fi amplifier facilitates speed-dependent equalization of the noises attributed to the vehicle acoustics by increasing the volume in a defined sound range. For this purpose, the Top hi-fi amplifier features a signal connection (speedometer A signal) from the instrument cluster. This equalizing function does not cause a general increase in the volume but rather the volume is increased depending on the sound pitch. The low frequency range in particular is boosted at high driving speeds.
The Top hi-fi amplifier features and additional two-channel subwoofer module. It is attached to the subwoofer housing, it has its own power supply and is switched on by a signal from the Top hi-fi amplifier (> 8 V = ON / < 6 V = OFF). In the same way as the Top hi-fi amplifier, the subwoofer module features speed-dependent equalization of the noise attributed to the vehicle acoustics. For this purpose, the subwoofer module is equipped with a signal connection (speedometer A signal) from the instrument cluster via the Top hi-fi amplifier. The low frequency range in particular is boosted at high driving speeds.
The Top hi-fi amplifier features a spatial sound function which enables improved space acoustics. The spatial sound effect is particularly effective in conjunction with ”pure” sound sources (CD mode). The spatial sound function is not recommended for predominantly voice reproduction or poor radio reception. The spatial sound function is switched on after terminal ”R” has been activated (ignition lock in position 1) and can be switched off by means of the Ergocommander.