Rebec RPX-B12S V2 – 12-Channel DSP Amplifier with Four High-Power Channels

Product Overview

The Rebec RPX-B12S V2 is a 12-channel Class D DSP amplifier from Rebec’s RPX-B Series, designed for car audio systems requiring a large number of independently amplified channels together with flexible power distribution.

Unlike a conventional multi-channel amplifier where every channel provides the same output, the RPX-B12S V2 divides its twelve amplifier channels into two groups. Channels 1–8 provide 50W RMS per channel at 4Ω, while channels 9–12 provide 100W RMS per channel.

This 8+4 power architecture allows the amplifier to handle multiple speaker sections while reserving four higher-power channels for loudspeakers requiring greater output.

Combined with twelve DSP outputs, dual AP5688 processing, PC tuning and multiple analog and digital inputs, the RPX-B12S V2 provides an integrated platform for complex active car audio systems.

12-Channel Class D Amplification

The RPX-B12S V2 incorporates twelve channels of Class D amplification.

At 14.4V and 4Ω, the rated output is:

50W RMS × 8CH (CH1–8) + 100W RMS × 4CH (CH9–12), at 0.1% THD.

At 3Ω, output increases to:

66W RMS × 8CH + 130W RMS × 4CH, at 0.1% THD.

The difference between the two channel groups is significant for system configuration. Rather than simply increasing the total number of channels, the RPX-B12S V2 provides different power levels for different loudspeaker requirements.

The first eight channels can handle speaker sections requiring moderate amplification, while channels 9–12 provide twice the rated 4Ω power for more demanding sections.

Four Higher-Power Channels

Channels 9–12 are a key part of the RPX-B12S V2 architecture.

In addition to providing 100W RMS ×4 at 4Ω, these four channels support 200W RMS ×4 at 2Ω, measured at 0.1% THD.

This gives the system designer considerably more power from these channels when working with compatible lower-impedance loads.

The four channels also support bridge operation. At 4Ω, CH9+10 and CH11+12 can be configured to provide:

200W RMS ×2 bridged channels.

This creates several possible approaches to power distribution within the same DSP amplifier, depending on the loudspeaker configuration and system requirements.

Built for Complex Active Systems

With twelve amplified channels available, the RPX-B12S V2 can directly support substantially more independently driven loudspeakers than lower-channel DSP amplifiers.

Rebec identifies the model as a solution for configurations such as a 3-way active front system combined with a 2-way active rear system, while providing additional power capability.

The twelve-channel architecture also gives installers greater freedom in assigning amplifier channels according to the actual system design.

Rather than relying on one uniform power level across the entire system, different speaker sections can be assigned to either the 50W or 100W channel groups according to their amplification requirements.

12-Channel DSP Output

The RPX-B12S V2 provides twelve low-level output channels at 2.2V, matching the scale of its twelve-channel amplifier architecture.

These processed outputs allow the DSP platform to work with external amplification when required.

This means the RPX-B12S V2 does not have to operate solely as an all-in-one twelve-channel amplifier. External amplifiers can still be incorporated into the system when a particular speaker section or subwoofer requires a different amplification solution.

The processor can therefore remain the central signal-management platform even in a larger system using additional power amplifiers.

Dual AP5688 DSP Processing

The RPX-B12S V2 uses two AP5688 DSP chipsets.

DSP processing operates at a 48kHz sampling frequency, with a specified dynamic range of 93dB.

For acoustic adjustment, the processor provides a 31-band EQ and crossover processing with Butterworth, Linkwitz and Bessel filter types.

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

Tuning is performed through PC software, allowing the twelve-channel system to be configured from a centralized DSP environment.

Multi-Channel Factory Integration

The RPX-B12S V2 provides 12 high-level inputs supporting 7.9–24.9Vpp, allowing integration with compatible multi-channel factory audio systems.

Two low-level analog inputs supporting 1.3–5.1Vpp are also available.

The twelve-channel high-level input architecture is particularly relevant when the original vehicle audio system provides multiple independently amplified signals that need to be integrated into the aftermarket DSP system.

192kHz/24-Bit Digital Audio Inputs

For digital sources, the RPX-B12S V2 provides both Optical (Toslink) and Coaxial inputs supporting up to 192kHz/24-bit.

A USB Audio input is also provided, together with built-in Bluetooth 5.4.

These interfaces give the processor several digital source options in addition to its high-level and low-level analog inputs.

DSP, DAC and ADC Architecture

The signal-processing platform combines the dual AP5688 DSP configuration with a CJC4344 DAC and ES7210 ADC.

Frequency response is specified from 20Hz to 20kHz, with a signal-to-noise ratio of 95dB.

Total harmonic distortion is specified at below 0.08% for both low-level and high-level signals.

The complete unit operates from 10–16V and measures approximately 271 × 228 × 53 mm.

More Channels and More Flexible Power Distribution

The Rebec RPX-B12S V2 represents a significant step in channel capacity compared with the RPX-B1012.

Rather than simply adding two more amplifier channels, it introduces a 12-channel architecture with two distinct power groups: eight channels rated at 50W RMS and four channels rated at 100W RMS at 4Ω.

The four higher-power channels can also provide 200W RMS ×4 at 2Ω or be configured as 200W RMS ×2 bridged at 4Ω, giving the amplifier greater flexibility when different loudspeaker sections require different levels of power.

Combined with 12-channel DSP output, dual AP5688 processing, 31-band EQ, multiple crossover filter types, six presets, 192kHz/24-bit Optical and Coaxial inputs, USB Audio and Bluetooth 5.4, the RPX-B12S V2 provides a flexible integrated platform for complex multi-channel car audio systems.

Rebec RPX-B12S V2

12-Channel Class D DSP Amplification with an 8+4 Power Architecture for Flexible Multi-Way Active Car Audio Systems.