Rebec RPX-B812 – 8-Channel Class D DSP Amplifier with 12-Channel Output

Product Overview

The Rebec RPX-B812 Black is a multi-channel DSP amplifier from Rebec’s RPX-B Series, combining eight channels of Class D amplification with twelve channels of low-level DSP output.

With 50W RMS available across all eight amplified channels at 4Ω, the RPX-B812 provides considerably more integrated channel capacity for active and multi-speaker car audio systems. Its twelve processed low-level outputs also allow the system to extend beyond the internal amplification when additional external amplifiers are required.

The RPX-B812 supports factory high-level integration, low-level analog input, USB Audio, 192kHz/24-bit Optical and Coaxial digital inputs, Bluetooth 5.4 and PC-based DSP tuning.

8-Channel Class D Amplification

The Rebec RPX-B812 uses a Class D amplifier topology with eight built-in amplified channels.

At 14.4V and 4Ω, the amplifier delivers:

50W RMS × 8CH at 0.1% THD.

At 3Ω, output increases to:

66W RMS × 8CH at 0.1% THD.

Unlike designs where different channel groups provide different output levels, the RPX-B812 Black provides the same rated power across all eight amplifier channels. This makes channel allocation more straightforward when building multi-way active systems.

The eight-channel architecture also reduces the need for additional amplification in systems requiring a larger number of independently powered loudspeaker channels.

Designed for Multi-Way Car Audio Systems

The additional amplifier channels give the Rebec RPX-B812 greater flexibility when configuring active car audio systems.

Rebec identifies the RPX-B812 as a solution capable of supporting a 3-way active front system combined with a 2-way passive rear system.

In such a configuration, six amplifier channels can be assigned to the left and right tweeter, midrange and midbass drivers of the active front stage, while the remaining two channels can power the passive rear speakers.

This is one example of how the eight-channel architecture can be used. The actual channel assignment can be adapted according to the loudspeaker configuration and tuning strategy of the installation.

12-Channel DSP Output for Expansion

While eight channels of amplification are integrated into the Rebec RPX-B812, its processing architecture extends to twelve low-level output channels.

These outputs are specified at 2.2V and allow processed audio signals to be routed to external power amplifiers.

This means a system can use all eight internal amplifier channels for the main loudspeakers while retaining additional processed outputs for other sections requiring separate amplification, such as a subwoofer.

The RPX-B812 Black can therefore function as an integrated eight-channel DSP amplifier while also providing the signal-processing capability required for a larger multi-amplifier system.

Dual AP5688 DSP Architecture

Signal processing in the Rebec RPX-B812 is handled by two AP5688 DSP chipsets.

The system operates at a 48kHz DSP sampling frequency and provides a 31-band EQ for detailed frequency adjustment.

Its crossover section supports Butterworth, Linkwitz and Bessel filter types, giving the tuning platform multiple filter options for defining the operating range of different loudspeaker channels.

The processor also provides six presets for saving and recalling tuning configurations.

System tuning is performed through PC software, providing centralized control over the DSP configuration.

192kHz/24-Bit Digital Inputs

Another notable aspect of the Rebec RPX-B812 is its digital input capability.

Both Optical (Toslink) and Coaxial inputs support signals up to 192kHz/24-bit, providing direct digital connection for compatible source devices.

The RPX-B812 Black also includes USB Audio input and built-in Bluetooth 5.4.

For analog integration, the processor provides 12 high-level input channels supporting 7.9–24.9Vpp, making it suitable for integration with multi-channel factory audio systems.

Two low-level inputs supporting 1.3–5.1Vpp are also provided for compatible analog sources.

DSP, DAC and ADC Signal Architecture

Alongside its dual AP5688 DSP configuration, the RPX-B812 uses a CJC4344 DAC and ES7210 ADC within its signal architecture.

The processor has a specified frequency response of 20Hz–20kHz, a dynamic range of 93dB, and a signal-to-noise ratio of 94dB.

Total harmonic distortion is specified at below 0.09% for both low-level and high-level signals.

These specifications describe the signal platform supporting the RPX-B812’s twelve-channel processing and eight-channel amplification architecture.

Integrated Multi-Channel System Design

The Rebec RPX-B812 measures approximately 197 × 208 × 50 mm and operates from a 10–16V automotive electrical supply.

Within this chassis, Rebec combines eight Class D amplifier channels, twelve-channel DSP output, multi-channel factory input capability and several digital source interfaces.

This integrated approach can reduce the number of separate components required for a multi-way active system while still retaining the ability to add external amplification through the twelve low-level outputs.

More Channels for More Flexible System Configuration

The Rebec RPX-B812 is built around two main capabilities: eight channels of integrated Class D amplification and twelve channels of DSP output.

With 50W RMS × 8CH at 4Ω, it provides enough internal channels to directly manage more complex loudspeaker configurations, including the 3-way active front and passive rear arrangement identified by Rebec.

At the same time, twelve processed low-level outputs provide room for additional external amplification when the system needs to extend beyond the eight built-in channels.

Combined with dual AP5688 DSP processing, 31-band EQ, multiple crossover types, six presets, 192kHz/24-bit Optical and Coaxial inputs, USB Audio and Bluetooth 5.4, the RPX-B812 provides a flexible platform for multi-channel DSP-based car audio installations.

Rebec RPX-B812

8-Channel Class D DSP Amplification with 12-Channel Processing for Flexible Multi-Way Car Audio Systems.