Brax RX2 Pro - 2 Channel Amplifier

The BRAX RX2 PRO combines compactness and efficiency in an impressive way, with technical and sonic attributes that elevate amplifier quality standards to a whole new level. In close collaboration with the Danish manufacturer PURIFI, a unique and uncompromising concept was realized based on their patented EIGENTAKT technology — a concept that dispels all previous prejudices against digital amplification.

All performance metrics, including Total Harmonic Distortion (THD+N), intermodulation, and signal-to-noise ratio, are so extraordinary that only the most expensive measurement systems can accurately capture them. The foundation of this exceptional performance is the Multi-Stage Feedback principle, in which several extremely broadband and therefore ultra-fast feedback loops in the amplifier stages compensate for all non-linearities.

This even extends to the output relays, which have their own control loop to equalize their minimal contact resistance. Crucially, the LC output filter required for Class D amplifiers is incorporated into these feedback loops, completely compensating for its significant impact on distortion and output impedance.

The RX2 PRO thus shines with phenomenal values for a damping factor of 10,000—not just at the typical test frequency of 1 kHz, but across the entire audio band. Additionally, the frequency response dependency on the load, typical of Class D amplifiers, is eliminated with this circuit topology. No matter which speaker the RX2 PRO drives, its amplitude response remains perfectly linear up to 60 kHz across all impedances.

Advanced Power Supply Design

Another key to the unmatched sound quality of the RX2 PRO is the extensive effort put into its power supply design. The power supply is regulated, providing a constant output voltage to the power stages that is independent of the battery voltage. This ensures full start-stop capability and allows operation in electric vehicle onboard networks, where voltages up to 18 volts can occur.

Additionally, the power supply is equipped with a total of 67 electrolytic capacitors with massive total capacity, ready to deliver enormous impulse currents when needed. To ensure that the PCB does not hinder current flow, eight layers of copper minimize internal resistance. But that's not all: The high number of layers also brings other advantages, ensuring that high currents have no impact on sensitive input or feedback signals, thanks to the sophisticated layout.

Flexible Input Options with First-Class Signal Processing

The analogue input module introduces the new "Super-Balanced" principle, where two extremely low-noise and low-distortion BurrBrown OPA1612 operational amplifiers form a differential input stage per channel. This not only handles amplification but also ensures an extremely high common-mode rejection ratio, providing excellent immunity to automotive-related interference on the input signals.

The digital input module, equipped with both optical and coaxial SPDIF digital inputs, shines with a state-of-the-art Digital-to-Analogue Converter (DAC) from ESS. This DAC achieves performance metrics previously unattained in the car audio segment, with a signal-to-noise ratio of 130 dB and a distortion figure of -117 dB (equivalent to 0.00014%).

These outstanding values are made possible by the meticulous design of the power supply for the DAC. A dual voltage regulator, developed specifically by ESS, supplies each channel separately with extremely low-noise and highly stable operating voltage. As part of a logical, holistic concept in line with BRAX standards, the digital input module also supports the proprietary DiSAC 2.0 protocol of the BRAX DSP for unparalleled volume control at the end of the signal chain.

Compact Design and Revolutionary Efficiency

In addition to its unbeatable technical highlights, the RX2 PRO presents itself in an exceptionally elegant and compact form. Despite its enormous output power of 2 x 300 watts at 4 ohms or 2 x 510 watts at 2 ohms (or 1 x 930 watts at 4 ohms), it has the same size as a BRAX DSP and is nearly 40% more compact than a GX2000, or even 66% smaller than an MX4 PRO.

In terms of efficiency, power consumption and reduced heat generation, the RX2 PRO opens a completely new chapter for BRAX, aligning with the general trend towards higher packing density and increased efficiency.

Features

• Proprietary bridgeable high-end Class D amplifier concept based on PURIFI's patented 'EIGENTAKT' technology - redefining automotive sound quality and outperforming even the best Class A and Class AB amplifiers
• Unique 'Multistage Feedback Design' - multiple feedback loops individually compensate for all non-linearities in the power section, including the LC filters and even the output relays, for absolute precision.
• Outstanding measurement values – outperforming everything thanks to negligible THD+N, minimal intermodulation distortion (IMD), an impedance-unaffected, linear frequency response up to 60 kHz and an impressive signal-to-noise ratio
• Modular input concept with selectable modules - offers a choice between analog or digital inputs
• Analog stereo input module - with innovative ‘super-balanced’ input structure for particularly high interference immunity thanks to maximum Common-Mode Rejection (CMR), equipped with the currently best sounding and ultra-low-noise OPA1612 operational amplifiers from BurrBrown
• Digital stereo input module - equipped with the latest state-of-the-art ES9039Q2M DAC from ESS, powered by a voltage regulator specially developed by ESS to provide each DAC channel with an extremely low-noise and stable power supply. Equipped with an optical and a coaxial SPDIF input that supports our proprietary DiSAC 2.0 protocol for lossless and highly advanced volume control, manageable via the BRAX DSP
• Incomparably sophisticated power supply - regulated, start-stop-capable power supply unit for the output stages with enormous total capacity for maximum peak current capability. Separate voltage regulators for each input and driver stage guarantee maximum stability and prevent any influence on the signal quality; suitable up to 18V on-board voltage for electric vehicles
• Exceptional frequency-independent damping factor of over 10,000 @ 4 ohms - unlike conventional Class D designs, this ensures maximum speaker control at all frequencies, resulting in unrivalled audio precision.
• Particularly compact and maximum efficiency - same dimensions as a BRAX DSP, ideal for modern vehicle concepts thanks to low heat generation and high efficiency
• Ultra-low impedance 8-layer printed circuit board - allowing maximum, loss-free current flow and optimum isolation of sensitive input signals from the power stages
• Exclusive use of the finest and selected components - guarantees maximum consistency and remarkable durability
• Complex protection circuits - Optimum protection of the amplifier and the connected speakers under all conceivable load and temperature conditions
• Processor and temperature-regulated fan - ensures optimum cooling and an ideal operating temperature range for the amplifier
• Separate connector for the BRAX Power Stabiliser - for an increased power supply and improved maximum performance of the amplifier
• Massive heat sink made of a special aluminum alloy - enables optimum heat dissipation and continuously high performance
• Engraved serial number in the stainless steel type plate - emphasises the exclusivity of the amplifier
  

What's in the Box?

• 1 x High-End Amplifier BRAX REVELATION RX2 PRO
• 1 x BRAX REVELATION T-shirt
• 3 x Allen key
• 1 x Certificate
• 1 x Audio Precision measurement report
• 1 x Instruction manual

Technical Specifications

Output Power RMS ≤ 1% THD+N RX2 PRO with digital input module

• @ 4 Ohms: 2 x 300 Watts
• @ 2 Ohms: 2 x 510 Watts
• bridged @ 4 Ohms: 1 x 930 Watts

Inputs

• 1 x Optical SPDIF (32 - 96 kHz)
• 1 x Coaxial SPDIF (32 - 192 kHz)
• 1 x Remote In
• 1 x Power Stabilizer Input

Specs

• Amplifier technology: PURIFIs "EIGENTAKT" Class D
• Outputs: 2 x Speaker output
• Signal converter for digital input: ESS 9039Q2M with HyperStream IV Dual DAC technology and advanced ­SABRE HiFi architekture / Supports ­Audiotec ­Fischers proprietary DiSAC technology
• Frequency response: 10 Hz - 60 kHz
• Signal-to-noise ratio digital input: > 125 dB (A-weighted)
• Distortion (THD): < 0.0002 %
• Damping factor: > 10,000
• Operating voltage: 9 - 18 Volts  (max. 5 sec. down to 6 Volts)
• Idle current: 1.5 A
• Power rating: DC 12 V ⎓ 150 A max.
• Fuse: 4 x 25 A LP-Mini-fuse (APS)
• Operating temperature range: -20 °C to +70 °C
• Additional features: Based on Purif's EIGENTAKT technology, BRAX Power Stabilizer connector, Start-Stop capability, input mode switch
• Dimensions (H x W x D): 56 x 310 x 200 mm
• Net weight: 4.0 kg

Further Information

Brax RX2 Pro - User Manual (PDF)