BRAX MX4 PRO 4 High End 4 - Channel Amplifier

Can you make the best amplifier in the world even better? Our engineers were faced with this enormous challenge when developing the MX4 PRO. Because at the level of a BRAX product, it is important to constantly question and optimize every detail, even if it seems insignificant at first glance. Only in this way is it possible to keep pushing the boundaries - in terms of sound and technology. Ultimately, we succeeded in redefining the standards in amplifier construction with the MX4 PRO. It is the perfect symbiosis of the most modern components and congenial improvements in circuitry, without neglecting the previous virtues and traditions for which the BRAX brand enjoys the highest reputation worldwide.

So it is still a matter of course that Audiotec Fischer is the only manufacturer to use exclusively hand-selected transistors for the production of each BRAX amplifier, which are divided into over 300 classes using self-developed measuring devices and compiled accordingly. This unique process not only guarantees the smallest series tolerances, but above all unique measurement and performance values.

Above all, the enormous effort that goes into the power supply of all assemblies has a significant share in the overall performance. Separate and stabilized power supplies for two channels each guarantee optimal working conditions for the individual amplifier stages. The electrolytic buffer capacitors specially manufactured for Audiotec Fischer with extremely low internal resistance thanks to 8-way contacts have become just as legendary as the encapsulated high-performance toroidal transformers, which can shake more than 1,800 watts of power out of the sleeve. A completely revised printed circuit board layout with four solid copper layers ensures maximum power delivery capability - so it is not surprising that

But that's not all - the MX4 PRO is also a prime example of bridging the gap between analog amplifier technology and the digital age. A hitherto unique effort is made to regulate the volume of the digital signal inputs. Because as an absolute novelty in the car audio segment, the signal level is controlled here in connection with the BRAX DSP without reducing the digital resolution directly before the output stages, which drive the loudspeakers and are therefore completely loss-free in the analog signal level. The BRAX DSP embeds the volume information in the digital SPDIF data stream and decodes it again in the MX4 PRO. This alone illustrates the striving of our engineers for absolute perfection.

And this meticulousness is of course continued in production. Each individual device is manufactured exclusively to order and individually according to customer requirements and recorded in a service database with the associated serial number. This makes each amplifier a real one-of-a-kind, which can rightly be adorned with the title "High-End made in Germany".

features

• 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 circuit board layout with quadruple multilayer base board for maximum current and signal flow and higher output power

• Lossless switching of the input signals via relays with gold-plated contacts

• Largest possible renunciation of coupling capacitors in the signal path for the best possible impulse response

• Enormous damping factor of over 1,400 @ 4 ohms for maximum speaker control

• Maximized signal-to-noise ratio through power supply synchronization

• Extremely complex, regulated switching power supply

• Eightfold contacted electrolytic capacitors with a total capacity of 40,000 µF and the lowest possible internal resistance as well as a 300 A interference suppression choke for buffering the pulse currents on the operating voltage

• Separate connection for BRAX Power Stabilizer

• Loudspeaker protection circuit via the highest quality high-current power relay

• Specially developed toroidal transformers made from highly permeable core materials with the highest possible saturation currents

• 32 hand-selected high-end MOSFET transistors for the lowest tolerances and optimal measured values

• Engraved serial number in 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 base plate

• Solid heat sink made from a special aluminum alloy for optimal cooling of the power supply and output stage transistors

Special Features:

DiSAC (Digital Signal Analog Controlled) volume control in connection 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. the car radio):
This method is used most frequently, 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 Source volume is set to maximum. Otherwise, bits are "lost", so that the precision of the sound suffers, especially when the volume is set very low. However, this loss can occur even when there is no DSP between the radio and the amplifier, as most radios today include 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 the maximum signal level so that the downstream DSP is always optimally controlled and no information is lost, for example during AD conversion. The volume is then controlled digitally in the signal processor via a remote control connected to the DSP, which, however, is not entirely possible without loss of sound at very low volumes.

The perfect solution

In connection with the BRAX DSP, the MX4 PRO therefore follows the most consistent and most complex route when adjusting the volume with the exclusive, proprietary "DiSAC" technology in order to avoid losses in sound from the outset. This principle works optimally when the signal source itself either does not contain any volume control or is set to a high basic volume. The signal is thus always further processed in the BRAX DSP at the ideal level without reducing the resolution at any point. Either the URC.3 remote control or the DIRECTOR is used to set the desired volume.
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 DA converters. Thus, the volume setting takes place without loss at the ideal point, i.e. only directly before the power stages that drive the loudspeakers.
This type of volume control is absolutely unique in the car hi-fi sector and shows that no effort was spared with this amplifier to redefine the tonal standard.

start-stop capability

The power pack in the MX4 PRO ensures the internal power supply even in the event of short-term dips down to 6 volts. This ensures that the MX4 PRO remains fully functional even when the engine is started.

Technical specifications

Power RMS

@ 4 ohms 4 x 300 watts

@ 2 ohms 4 x 300 watts

@ 1 ohms 4 x 300 watts

Bridged to 4 ohms2 x 600 watts

Bridged to 2 ohms2 x 600 watts

Amplifier Technology Class AB

Inputs

4 x RCA
2 x Optical SPDIF (32 - 96 kHz)
2 x Coaxial SPDIF (32 - 192 kHz)
1 x Remote In

Input Sensitivity RCA 1.0 - 8.0 volts

Input impedance RCA 10k ohms

Output 4 x speaker output

Signal converter for the digital input BurrBrown 24-bit DA converter

Frequency Range 10Hz - 80kHz

Signal to noise ratio digital input > 116 dB (A-weighted)

Signal-to-noise ratio analog input > 116 dB (A-weighted)

Total Harmonic Distortion (THD) <0.0005%

Damping Factor > 1400

Operating Voltage 9 - 16 volts (max. 5 sec down to 6 volts)

No-load Current Consumption 8.5A

Fuse 6 x 25A LP mini plug-in fuse

Additional features Color Protection System, BRAX Power Stabilizer connection, start-stop capability

Dimensions (H x W x D) 79mm x 360mm x 360mm

Net Weight 12.0kg