SKU: 16357591583

BRAX MX4 PRO - Black 4 Channel Amplifier

Sale price$1853.99 Regular price$2059.99
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Description

BRAX MX4 PRO - Black 4 Channel AmplifierBRAX MX4 PRO Is it possible to make the best car audio amplifier worldwide even better? This was really a challenge for our engineers when they started the development of the MX4 PRO. When designing a BRAX product it is essential to reconsider and optimize every single detail again and again, even if it seems to be less significant at first sight. From our understanding this is the one and only approach how to shift the limits acoustically and

BRAX MX4 PRO

Is it possible to make the best car audio amplifier worldwide even better? This was really a challenge for our engineers when they started the development of the MX4 PRO. When designing a BRAX product it is essential to reconsider and optimize every single detail again and again, even if it seems to be less significant at first sight. From our understanding this is the one and only approach how to shift the limits – acoustically and technically – further and further. Finally we are absolutely convinced that the MX4 PRO redefines the benchmark for amplifiers once again.

This masterpiece is the perfect symbiosis of state-of-the-art components and ingenious technological improvements without neglecting the heritage and the tradition of the brand that BRAX is famous for.
As the only manufacturer we still take it for granted to manually select power transistors for the production of each BRAX amplifier – and it is no secret that the necessary instruments and tools for this selection procedure are in-house developments. This one-of-a-kind process not only assures lowest possible serial tolerances but as well unrivalled measurement and power data.

A significant proportion for the overall performance is based on the extensive effort that is made for the power supply of all modules inside our amplifiers. Separate and stabilized supply voltages for each two channels warrant perfect conditions for every amplifier stage. The ultra-low ESR electrolytic capacitors (specially made for Audiotec Fischer) are meanwhile as legendary as our encapsulated toroid power transformers that come up with more than 1,800 watts power supply output just like that. A completely revised PCB design with four massive copper layers in total assures maximum current flow – so it is no wonder that the MX4 PRO with its mere 4 x 300 RMS into 4/2/1 Ohms delivers more power to the speaker terminals than ever before.

But that's not enough – the MX4 PRO is as well a paradigm for bridging the gap between traditional amplifier technology and the digital era.  We have made an unparalleled effort just for the volume control of the digital inputs. As a novelty in the car audio segment the volume adjustment in combination with the BRAX DSP takes place just before the output stages that drive the speakers - needless to say that this happens in the analog domain without sacrificing any signal resolution. The BRAX DSP embeds the volume information in the digital SPDIF data stream which then is decoded inside the MX4 PRO.

This aspect alone proves the striving of our engineers for pure perfection – and please rest assured that this meticulousness is set to continue throughout the entire production process. Each single amplifier is custom-made on demand and its respective serial number is recorded in our data-base. Therefore every BRAX MX4 PRO is a precious unique product that rightly deserves the title “high-end made in Germany”.

Features

  • Two digital stereo digital inputs in SPDIF format (optical and electrical) with a sampling rate up to 192 kHz
  • DiSAC (Digital Signal Analog Controlled) volume control for the digital signal inputs, controllable via BRAX DSP
  • Optimized quad-layer PCB design for maximized power and signal flow and increased output power
  • Lossless switching of the input signals via relays with gold-plated contacts
  • Best possible impulse response due to abstinence of coupling capacitors in the signal path
  • Incredible damping factor of more than 1,400 @ 4 Ohms for perfect speaker control
  • Maximized signal-to-noise ratio due to power supply synchronization
  • Extremely complex and regulated switch-mode power supply
  • Eightfold-contacted capacitors with a total capacitance of 40,000 μF and lowest possible ESR as well as a 300 A suppressor choke coil to smooth power supply peak currents
  • Separate connector for BRAX power stabilizer
  • Loudspeaker protection circuit via sophisticated high current power relays
  • Specially designed toroidal transformers made of high permeability core materials for highest possible saturation currents
  • 32 hand-selected high-end MOSFET transistors for lowest tolerances and outstanding measurement data
  • Engraved serial number on a stainless steel plate
  • Impedance independent output power of  300 Watts RMS per channel
  • 4, 2 and 1 Ohms stable
  • Processor and temperature controlled fan in bottom plate
  • Massive heat sink made of a special aluminum alloy for optimum cooling of all power transistors

 

Special features:

DiSAC (Digital Signal Analog Controlled) volume control in combination with the BRAX DSP

In a car audio system there are typically two possibilities to control the playback volume.
a) The volume will be adjusted in the signal source (e.g. the car radio / head unit):
This is the predominant method, but it has a disadvantage as soon as there is an additional digital signal processor in the audio path. The full resolution of the DSP can only be exploited when the volume of the source is set to full-scale output. Otherwise audio bits get “lost” so that at very low volume levels the sound lacks of precision. But this loss can also happen if no DSP is in the signal path between head unit and amplifier as most of the radios today incorporate a digital volume control which also has a negative effect on the signal resolution at low volume levels.
b) The volume will be adjusted in the digital signal processor (DSP):
In this case the signal source delivers a full-scale signal so that a DSP in the signal path can operate under best possible conditions without truncating any bits, e.g. during AD conversion process. A remote control connected to the DSP will then be responsible for adjusting the volume inside the signal processor in the digital domain, but this also has a slight impact on sound quality.

The perfect solution:

The MX4 PRO in combination with the BRAX DSP follows a different, yet the most consequent and extensive approach in order to avoid any degradation of sound quality. Audiotec Fischers exclusive and proprietary “DiSAC” technology operates perfectly if either the audio source does not incorporate any volume adjustment or the source always delivers a high signal level. In that case the audio processing inside the BRAX DSP is done without reducing the audio resolution at any time. For adjusting the playback volume either the cable remote URC.3 or the display remote DIRECTOR can be chosen.
The speciality lies in the fact that the volume information from the remote will be encoded inside the BRAX DSP and embedded into the digital audio data stream of the SPDIF outputs and thus transferred to the MX4 PRO.
The MX4 PRO itself is able to extract and decode the volume information from the digital data stream, using this to adjust the lossless analog volume controllers (PGA’s) after the DA converters. This simply means that the volume control takes place in the signal path where it does not have any negative impact on sound quality, actually just before the output stages that drive the loudspeakers.
This type of volume control is truly an uniqueness in the car audio segment and proofs once again that Audiotec Fischer didn’t spare any effort to redefine the pinnacle of sound quality once again.

Start-Stop capability

The switched power supply of the BRAX MX4 PRO assures operation even if the battery’s voltage drops down to 6 Volts during engine crank.

Technical data

Output power RMS  
- @ 4 Ohms 4 x 300 Watts
- @ 2 Ohms 4 x 300 Watts
- @ 1 Ohm 4 x 300 Watts
- bridged @ 4 Ohms 2 x 600 Watts
- bridged @ 2 Ohms 2 x 600 Watts
Amplifier technology Class AB
Inputs 4 x Cinch
2 x Optical SPDIF (32 - 96 kHz)
2 x Coaxial SPDIF (32 - 192 kHz)
1 x Remote In
Input sensitivity RCA / Cinch 1.0 - 8.0 Volts
Input impedance RCA / Cinch 10 kOhms
Input impedance highlevel
Outputs 4 x Speaker output
Output voltage RCA / Cinch
Signal converter for digital input BurrBrown 24 Bit DA converter
Frequency response 10 Hz - 80 kHz
Bass boost
Highpass
Lowpass
Bandpass
Subsonic
Phase
Slope high- / lowpass
Slope subsonic / lowpass
Signal-to-noise ratio digital input > 116 dB (A-weighted)
Signal-to-noise ratio analog input > 116 dB (A-weighted)
Distortion (THD) < 0.0005 %
Damping factor > 1400
Operating voltage 9 - 16 Volts  (max. 5 sec. down to 6 Volts)
Idle current 8.5 A
Fuse 6 x 25 A LP-Mini-fuse (APS)
Additional features Colour Protection System, BRAX Power Stabilizer connector, Start-Stop capability
Dimensions (H x W x D) 79 x 360 x 360 mm /
3.11 x 14.17 x 14.17"
Net weight 12.0 kg
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 16357591583

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4.8 ★★★★★
Based on 15 reviews
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A
Verified Purchase
Amazon Customer
Boise, US
★★★★★ 5
Love this chair!
Color: Black, Size: Pack of 1
I had an office chair that cost $300 more than this chair - had it for years, then things started breaking down on it. I read about this chair and, wow! I wish I had known about it sooner. It's more comfortable and it's not a chore to sit for a couple of hours working on designs. Wonderful design - supports my back well and it's very stable, easy to adjust.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 3, 2026
R
Verified Purchase
Rogelio Luna
West Palm Beach, US
★★★★★ 5
Genuine Quality
Color: Black, Size: Pack of 1
Absolutely love this office chair! Super comfortable, sturdy, and easy to adjust. It made a huge difference during long hours at my desk, and the quality feels excellent for the price. Highly recommend!
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Reviewed in the United States on May 21, 2026
J
Verified Purchase
Jon
Battle Creek, US
★★★★★ 3
Good chair with some quality issues
Color: Black, Size: Pack of 1
I've been using this chair for 12+ hours a day for the last 5 or 6 months and so far it is much better than my last chair I bought at Staples with a few problems. First, overall the chair is still comfortable when set properly, the cushion on the bottom is a little worn out but is still comfortable and I find the backrest comfortable except for the lumbar support which has very little cushioning and feels like a plastic brick being pushed into my back, however I find that I can keep it mostly out of the way most of the time and it isn't noticeable when I carry most of my weight on my upper back area while reclining. The reclining angle is super comfortable and the mesh on the back is not noticeably worn out. I like the headrest which is made of a cushioned mesh, its not better than a pillow but it's very comfortable to be able to rest your head in a chair you are going to sit in for long hours and gives good support. The arm rests don't feel amazing, they have a very stiff plasticky cushion feeling that I'm not much a fan of in terms of pure comfort but they get the job done as I mostly only rest my elbows on them when typing. The arm rest adjustment has a pretty good height range and I keep them at the highest settings and set as close to the chair as possible. While the chair may be comfortable, I have had some quality issues that bring down my opinion of the chair. First, my right arm rest does not go as high as my left arm rest and I have to set the left one down two positions to match the right one Second, the back rest locking for the upright position is broken but I can rarely get it to work as long as I don't put much weight on the back. I would imagine that most people would want to lock the chair upright as opposed to the other positions. Third, the 3 screws holding in the backrest untighten themselves over time, causing the backrest to move to its furthest back position and rock left or right if I lean on either side. When I tighten them again they will usually last about 1-2 weeks before becoming mostly loose again. There is no danger of the screws completely falling out though, just losing their tightness Lastly, I'm not sure how stable or secure the wood panel at the bottom of the seat that everything attaches to is strong enough, I used to have my armrests adjusted out further from the center but when I would lift up on my arms to adjust my seating position I would occasionally hear a sound of the wood stressing under the torque from the armrests. since I moved both armrests as close to the center as I can this has not happened; I would like them a little bit wider but I don't want to risk breaking the chair over it. Also, one of the factory-installed screws in the bottom seat panel fell out and wont stay back in but I haven't noticed any problems other than the risk of stepping on a screw caused by it While this is likely the most comfortable chair I've ever sat in, I have to give it 3 stars for the uncomfortable lumbar support and the quality control issues. If the QC issues were fixed I could easily give this chair a 4 star review
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Reviewed in the United States on March 20, 2022
W
Verified Purchase
Wes B.
Grantham, US
★★★★★ 5
Fantastic!
Color: Light Grey, Size: Pack of 1, Color: Light Grey, Size: Pack of 1
Outstanding quality and incredibly easy to assemble! The back support is a perfect 10/10. I was debating between the M57 and the B100, and the B100 definitely won me over. The materials feel premium and durable. Highly recommended!
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Reviewed in the United States on June 4, 2026
D
Verified Purchase
Dre
Fort Morgan, US
★★★★★ 5
Comfortable. Great Value for money. Easy to assemble. Great customer service.
Color: Black, Size: Pack of 1, Color: Black, Size: Pack of 1
I've been looking for a new chair to replace a cheap $30 chair i bought off of Amazon last year that had been killing my back and shoulders. I wanted something in the $150-$200 range and settled on the M18. Shipping was a fast 3 days with Prime and the box arrived in great condition. All parts were separately wrapped or in their own boxes. Came with all hardware and nothing was missing. Assembly took me a little longer then normal because i have rotator cuff injury in my left shoulder so that arm is mostly useless. The most difficult part for me was attaching the wheels to the base. Other then that it was simple. Once the chair was assembled i sat in it for the first time and started making my adjustments with the recline feature, armrest level along with the headrest. Next i reached around for the lumbar support knob and tried to adjust it but with my bad shoulder i decided to just get out of the seat and turn it around and adjust it with both hands. After spinning the chair a round to get at the lumbar knob i noticed a large crack in the plastic in the middle of the back of the lumbar plastic piece. I had not made any lumbar adjustments yet so i assumed this is how i received it. The lumbar support comes preinstalled to the backrest so it either was damaged before or during the shipping process. Either way it was damaged before being delivered to me. The lumbar support still functioned properly but it was still broken. I decided to contact Sihoo's customer support that came along with the installation instructions regarding the damaged lumbar piece. I received a reply the next day and after sending them some more info about my order and a couple pics they shipped me a replacement part which took a week to arrive. I swapped out the damaged part and after owning the chair for a week so far i am really happy with my purchase. Im about 5'10 180lbs. At its highest height level my feet reach the ground comfortably flat footed. The backrest fully covers my back and the headrest adjusts very well to sit on the back of my lower head/upper neck. The armrests only go up and down....not forward and back or tilt inwards. This is fine for me as they are grooved to fit your forearm while sitting at your desk/keyboard. The armrests are also a soft cushioned rubber material...not a hard plastic. The mesh of the backrest and headrest are good material and seem well made. The seat is very wide and the cushioning is firm which i prefer. Usually more firm cushioning seems to last longer and hold its form. The base of the chair is VERY sturdy and made of all metal. My chair is on carpet and holds its position very well. As far as recline goes you can set it to recline all the way back, half way or lock the chair in the upright position. You can also adjust the resistance on the reclining feature. So that being said im very happy with my purchase. It arrived with a slight flaw which the company corrected in a fast manor and was very polite in their customer support. I personally don't have a lot of experience with many office chairs and have never used a high end chair($500-$1000+) chair before to make any comparisons. All my chairs for the most part have been from local stores like Staples or Office Depot. Id recommend this over anything they carry in this price range....and i went and looked at their products before buying this chair as well.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 1, 2023

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