- Two digital stereo signal inputs in SPDIF format (optical and electrical) up to a sampling rate of 192 kHz
- DiSAC (Digital Signal Analog Controlled) volume control for the digital signal inputs, controllable via the BRAX DSP
- Optimized PCB layout with quad multilayer baseboard for maximum current and signal flow and higher output power
- Lossless switching of input signals via relays with gold-plated contacts
- Elimination of coupling capacitors in the signal path as far as possible for the best possible pulse behavior
- Enormous damping factor of over 1,400 @ 4 ohms for maximum speaker control
- Maximized signal-to-noise ratio through power supply synchronization
- Extremely elaborately designed, regulated switched-mode power supply
- Eight-contact electrolytic capacitors with a total capacitance of 40,000 μF and lowest possible internal resistance as well as 300 A interference suppression choke for buffering the pulse currents on the operating voltage
- Separate connector for BRAX power stabilizer
- Loudspeaker protection circuit via the highest quality high-current power relay
- Specially developed toroidal transformers made of highly permeable core materials with the highest possible saturation currents
- 32 hand-selected high-end MOSFET transistors for lowest tolerances and optimal measured values
- Engraved serial number in the stainless steel nameplate
- Impedance-independent output power of 300 watts per channel
- 4-, 2- and 1-ohm stable
- Processor and temperature-controlled fan in the bottom plate
- Solid heat sink made of a special aluminum alloy for optimal cooling of the power supply and power amplifier transistors
DiSAC (Digital Signal Analog Controlled) volume control in conjunction with the BRAX DSP
In a car hi-fi system, there are typically two different ways to adjust the volume.
a) The volume is controlled in the signal source (e.g.dem car radio):
This method is most commonly used, but has the disadvantage that when a digital signal processor (DSP) is controlled in the signal chain, its full signal resolution is only used if the volume at the source is set to maximum. Otherwise, bits are “lost”, so that the precision of the sound suffers, especially at very low volumes. However, this loss can occur even if there is no DSP connected between the radio and the amplifier, because most radios nowadays include a digital volume control, which is also lossy.
b) The volume is controlled in the digital signal processor (DSP):
In this case, the signal source always delivers maximum signal level, so that the downstream DSP is always optimally controlled and no information is lost, e.g. during AD conversion. Via a remote control connected to the DSP, the volume is then digitally controlled in the signal processor, which is not possible at very low volumes, however, without sound losses.
The perfect solution
The MX4 PRO, in conjunction with the BRAX DSP, therefore follows the most consistent and elaborate way to avoid sound losses from the outset when adjusting the volume with the exclusive, proprietary “DiSAC” technology. This principle works optimally if the signal source itself either does not contain any volume control or a high basic volume is set on it. The signal is thus always processed in the BRAX DSP at an ideal level without reducing the resolution at any point. To adjust the desired volume, either the URC.3 remote control or the DIRECTOR is used.
The special feature is that the volume information evaluated by the remote control in the DSP is embedded in the digital audio data stream of the SPDIF outputs of the BRAX DSP and thus transmitted to the MX4 PRO. In the MX4 PRO, this information is extracted from the data stream and used to control the analog volume controls behind the amplifier’s DACs. This means that the volume adjustment takes place losslessly at the ideal point, i.e. only directly before the power levels that drive the speakers.
This type of volume control is absolutely unique in the car hi-fi sector and shows that no effort has been spared with this amplifier to redefine the sound scale.