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Alpine R-A90S R-Series 6/5/4/3 Channel Power Amplifier with Staggered Power


Alpine R-A90S R-Series 6/5/4/3 Channel Power Amplifier with Staggered Power

  • Stock Status: In Stock
  • Available QTY : 1
  • Brand: Alpine
  • Model: R-A90S
  • EAN: 7426871623606
Ex Tax: £429.95
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Experience your music in Hi-Res with the R-A90S 6-channel R-Series amplifier. This is one of the most versatile Class-D 6-channel amplifiers on the market, featuring a unique staggered power channel layout that has double the power on the last two channels, as well as built-in high-pass and low-pass filters to build any kind of sound system.

The “R” line of speakers and subwoofers have a heritage of sound quality you can hear from a block away, and the newly added R-Series amplifiers are no exception. Aside from their best-in-class performance, these amplifiers are tuned to emphasize the characteristics of the R-Series speakers and subwoofers, giving you that legendary R-Series experience.

The Alpine R-Series Sound Components

The R-Series lineup is “The Loudest Family on the Block”. The products are designed to be played loud, delivering a fun and exciting listening experience, and are known for dependable performance and high-quality sound. All R-Series components are developed to perfectly match each other.

Staggered Power Design

With double the power on the last two channels, the R-A90’s 5th and 6th channels can be bridged to provide up to 500 Watts RMS @ 4 Ohms to your subwoofer system. The R-A90S has a unique staggered power channel layout, that has double the power on the last two channels. This means you can set the amp to deliver 4x 75 Watts + 2x 150 Watts to run 2 separate subs, or configure it 4x 75 Watts + 1x 500 Watts to run one very powerful subwoofer.

The Amp That Grows With You

Thanks to the unique staggered power channel layout, the R-A90S can host different levels of power on each channel, compared to traditional multi-channel amplifiers. The R-A90S can effectively function as both a 3-way active amplifier and a 5-channel amplifier by delivering the power you need to the channels where you need the most.

Accurate Sound Reproduction

Hear the subtle details you’ve been missing in your music. The R-A90S maintains an extremely low phase shift throughout the music spectrum, which minimizes audible imperfections in your music and allows your music to stay faithful to the original recording. With a hi-resolution frequency response, the R-A90S can reproduce sound with incredible accuracy that stays true to the artist’s intention.

Alpine Exclusive Technology

Using custom Alpine internal components originally launched in Alpine’s premium X-Series amplifiers, the R-A90S has dual “Sierra” post-filter feedback loops that correct signal distortion by making the output as close as possible to the original input for accurate sound reproduction.

Next Level System Builds

For the best possible sound experience, use the built-in band-pass, high-pass, or low-pass filter to individually power each component in your system and assign frequency bands for accurate and reliable sound reproduction.

Remote Bass Knob Ready

You can connect the RUX-KNOB2 remote bass knob (optionally available) to the R-A90S to control the subwoofer gain level (channel 5 + 6) straight from your dash.

Small Footprint and Installation Flexibility

Compact and Powerful: the new digital amplification circuit allows high power output while keeping a small footprint. The R-A90S measures just 324mm in width x 273mm in length for easy installation. The logo center-plate can be adjusted to install the amp in landscape or portrait orientation.

Thermal Protection

Along with Alpine’s new intelligent amplifier platform, the new R-Series amplifiers feature an improved heat sink and protection circuit design that eliminates thermal shut-down, for dependable music playback.

Low/High-Power Speaker Signal Inputs

The 6-Channel RCA speaker signal inputs accept low and high-power signals. This makes it easy to connect the R-A90S directly to your original car stereo, regardless of your head unit’s power output. The power cable terminal accepts heavy gauge cables of up to 4 AWG.

Best Performance with R-Series Speakers

The R-A90S is designed to perfectly match the Alpine R-Series speaker line for perfect system building. R-Series components are designed to be played loud, for a fun and great sounding experience.



  • Terminal Layout: One side
  • Small footprint for easy installation
  • Screw terminals (for speaker and power cables)


  • Amplifier Type: Class-D (Digital)
  • Channel Design: 6/5/4/3 Channel Design with Ch 5 + 6 Power Stagger Feature
  • Thermal Management Control
  • Top Mounted LED Power/Status Indicator
  • Speaker Level Input with remote turn on
  • Crossover: Adjustable Low-pass (LPF), High-Pass Filter (HPF) and Band-Pass Filter
  • Gain Control: Adjustable
  • Bass EQ
  • Remote Bass Control (RUX-KNOB2) Ready


Max Power Output Ratings

  • Total Max Power: 1800W

RMS Power Ratings

  • Per Channel into 2 Ohms, 14.4V (≤1%THD+N): 4 x 100W + 2 x 250W
  • Per Channel into 4 Ohms, 14.4V (≤1%THD+N): 4 x 75W + 2 x 150W
  • Per Channel into 4 Ohms, 14.4V (≤1%THD+N): 4 x 75W + 1 x 500W (bridged)
  • Per Channel into 4 Ohms, 14.4V (≤1%THD+N): 2 x 150W + 1 x 500W (bridged)

Sound Tuning

  • Variable HPF/HPF-H: 50Hz - 400Hz / 400Hz - 6kHz
  • LPF: 50Hz - 400Hz
  • BPF-L / BPF-H: 50Hz - 400Hz / 400Hz - 6kHz


  • Power Requirements: 14.4 V.DC (9 - 16 V allowable)
  • Input Sensitivity (RCA Input): Hi: 0.5V - 10V / Low: 0.2V - 4.0V
  • High Level Input with automatic power on
  • Cable size: Power Cable AWG 4, SPK Cable AWG 8
  • Frequency Response (+0/ -3dB: 1W into 4 Ohms): 10Hz - 45kHz
  • THD+N (@ 10W into 4 Ohms): <0.02%
  • THD+N rated power into 4 Ohms): <0.03%
  • Damping Factor: >500 (ref. 10W into 4 Ohms at 100Hz)
  • Signal to Noise (rated power into 4 Ohms): >103dB (Ch 1-4) / >106dB (Ch 5+6)
  • Weight: 4.52kg


  • Heat Sink (WxHxD) mm: 273 x 50.8 x 200
  • With attached brackets (WxHxD) mm: 273 x 50.8 x 324

We always recommends that you have your installation carried out by a qualified installer. Our experienced technical staff can take care of all kind of car audio upgrade jobs.

  • Car Stereo
  • Multimedia Audio Visual (Sat/Navs, Headrest Screens, Roof Screens etc.)
  • Speakers/ Subwoofers / Amplifiers
  • OEM Adapters Installation (DAB, iPod, iPhone, USB, Bluetooth, Aux)
  • Bluetooth Car Kit Installation
  • Car Security Alarms
  • Vehicle Tracking Systems
  • Reversing Camera / Parking Sensors
  • Dash Cameras

All installations are carried out at our London Installation center, Vehicle must be brought for installation.