Black car amplifier with multiple connectors on side.

Alpine R-A90S

$600.00

R Series 6-channel car amplifier — 75 watts RMS x 4 at 4 ohms + 250 watts RMS x 2 at 2 ohms

About the Alpine R-A90S

For loud and realistic-sounding music

Into high-res music? Alpine’s R-Series R-A90S amplifier reproduces high-frequency sounds up to 45,000 Hz, so you can enjoy the clean sound and enhanced realism you want in your music. Alpine applied some hot technology from their top-of-the-line X-Series amplifiers into this R-Series amp, including the use of high-efficiency transformers and premium custom capacitors in the amp’s construction. Dual “Sierra” feedback circuitry decreases distortion by correcting the output using the original input signal. Even if you’re playing CDs and standard-resolution music files, you can count on superior sound quality from this amplifier.

It’s not just about power

Alpine designed this amp to run a 3-way active system. Channel 1/2 can send a couple tweeters up to 75 watts RMS each and features a high-frequency high-pass filter necessary for safe tweeter operation. Channel 3/4 can send a pair of midrange drivers 75 watts RMS each and features a band-pass filter that keeps extreme highs and lows away from the midrange speakers. Channel 5/6 is for subwoofers, low-pass filter only, and can power two subs with up to 250 watts RMS each, or one sub with 500 watts.

For maximum overdrive

You could also use this amplifier to power two high-performance speakers with 200 watts each plus a sub with 500 watts for optimum power applications. In these cases you’d switch the crossovers from 3-way to 2-way operation. Whatever configuration you decide on, don’t forget to include the optional RUX-KNOB.2 remote bass knob to control your bass from the dash. Alpine R-A90S amplifier with adjustable controls.  
Alpine R-A90S control panel

Product highlights:

  • 6-channel car amplifier
    • 75 watts RMS x 4 + 150 watts RMS x 2 at 4 ohms
    • 100 watts RMS x 4 + 250 watts RMS x 2 at 2 ohms
    • 200 watts RMS x 2 bridged at 4 ohms + 500 watts RMS x 1 bridged at 4 ohms
  • Class D amp technology
  • Ch 1/2: selectable variable high-pass filter (50-400 Hz or 400-6000 Hz, 12 dB/octave)
  • Ch 3/4: variable high-pass or bandpass filter (50-400 Hz and 400-6000 Hz, 12 dB/octave)
  • Ch 5/6: variable low-pass filter (50-400 Hz, 12 dB/octave)
More Info:
  • GTO™ (Great Turn On) signal-sensing turn-on with Ch1/2 speaker-level input
  • preamp and speaker-level inputs
    • speaker-level inputs require RCA adapter cables
  • optional wired remote level controller available
  • fuse rating: 30A x 3
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • dimensions: 14″W x 2-1/16″H x 10-3/4″D
  • warranty: 1 year

What’s in the box:

  • Alpine R-A90S owner’s manual
  • 6-Channel amplifier
  • Three 30-amp ATO fuses (installed)
  • 4 Mounting feet
  • Four 3/4″ Screws
  • Eight M2.5×5.5mm Machine screws
  • 2mm Allen wrench
  • 3mm Allen wrench
  • Owner’s manual (English/ French/ Spanish)
  • Alpine Verification Certificate
  • Warranty information
  • Power supply note
  • On-line product registration information

More details on the Alpine R-A90S

Features & specs

Performance
RMS Power Output (Watts x Channels) 75 x 4
250 x 2
Peak Power Output (Watts x Channels) N/A
Power at 2 Ohms (Watts x Channels) 100 x 4
Power at 1 Ohm (Watts x Channels)
Bridged Power (Watts x Channels) 200 x 2
Minimum Impedance Bridged 4
Minimum Impedance Unbridged 2
Best Frequency Response 10-45k Hz
THD at Rated RMS Power 1%
Signal to Noise Ratio 85 dB
Input Voltage 14.4v
Features
Amplifier Class D
Built-in DSP No
Remote Control Optional
Low-Pass Crossover Frequency 50-400 Hz
Low-Pass Slope (dB/octave) 12 dB/octave
High-Pass Crossover Frequency 50-6000 Hz
High-Pass Slope (dB/octave) 12 dB/octave
Bass Boost No
Bass Boost Frequency N/A
Fan Cooled No
Fuse Rating 90
Speaker Level Inputs Yes
Preamp Outputs No
Width (inches) 14
Height (inches) 2-1/16
Depth (inches) 10-3/4
Parts Warranty 1 Year

Product Research

Features

Overview: The Alpine R-A90S 6-channel amplifier is effectively two full range amps built into one chassis, a 4-channel 4 x 75 watt (labeled Channel 1/2 and Channel 3/4), and a 2-channel 2 x 150 watt (labeled Channel 5/6). Each section of the amp is bridgeable, so it can be wired as 6-channel, 5-channel, 4-channel, or 3-channel.

CTA-2006 Compliant: CTA-2006 is a system of testing and measurement for mobile audio amplifiers. This voluntary standard advocates a uniform method for measuring an amplifier’s RMS power output and signal-to-noise ratio. The criteria for measuring amplifier power uses a DC input voltage of 14.4 volts and the RMS power output is measured over a frequency range of 20 Hz to 20 kHz (for full range amplifiers), with 1% or less Total Harmonic Distortion plus noise (THD+N). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4 ohms. CTA-2006 standards allow consumers to compare car amplifiers and receivers under the same conditions (apples to apples).

CTA-2006 Specifications:

  • Power Output: 75 watts RMS x 4 (channels 1-4) and 150 watts RMS x 2 (channels 5-6) into 4Ω
  • Signal to Noise Ratio: 85 dBA (measured at 1 watt into 4Ω)

Other Specifications:

  • Power Output:
    • 2Ω: 100 watts RMS x 4 (channels 1-4) and 250 watts RMS x 2 (channels 5-6); 14.4 volts, ≤1.0% THD+N)
    • Bridged: 200 watts RMS x 2 (channels 1-4) and 500 watts RMS x 1 (channels 5-6); 14.4 volts into 4Ω
  • Signal to Noise Ratio: 103 dB (channels 1-4) and 106 dB (channels 5-6); at rated power output, 4Ω

Hi-Res Frequency Response: The Alpine R-A90S offers a wide frequency range for compatibility with Hi-Resolution Audio.

  • +0/-3 dB (1W into 4Ω): 10 Hz – 45 kHz
  • +0/-1 dB (1W into 4Ω): 20 Hz – 20 kHz
Controls

Gain Control: There are independent rotary gain controls for channels 1/2, channels 3/4, and channels 5/6. The amp will accept line level signals from 0.2 volts to 4.0 volts or speaker level signals from 0.5 volts to 10 volts.

Input Level: Set the input level switch to match the type of input signal used (Hi for speaker level and Lo for line level).

Input Channel: There are two Input Channel switches to select which input feeds channels 3/4 and 5/6. Channels 1/2 are always fed by inputs 1/2.

  • Channel 3/4: 2-position switch; choose which inputs feed channels 3/4; 1/2 or 3/4
  • Channel 5/6: 2-position switch; choose which inputs feed channels 5/6; 1/2 or 5/6

Crossovers: Channels 1/2, 3/4, and 5/6 have independent crossovers. Each crossover has a switch to direct how it operates and all crossovers have a slope of 12dB/octave.

  • Channel 1/2:
    • Off: output is full range
    • HP: High Pass; crossover point is adjustable from 50 Hz to 400 Hz
    • HP-H: used when powering a pair of tweeters; crossover point is adjustable from 400 Hz to 6 kHz
  • Channel 3/4:
    • Off: output is full range
    • HP: High Pass; crossover point is adjustable from 50 Hz to 400 Hz
    • BP: Band Pass; two crossover points are set, high pass is adjustable from 50 Hz to 400 Hz and the low pass is adjustable from 400 Hz to 6 kHz
  • Channel 5/6:
    • Off: output is full range
    • LP: Low Pass; crossover point is adjustable from 50 Hz to 400 Hz

Optional Remote Control: The amplifier has an RJ-25 jack for adding the optional RUX-KNOB.2 wired remote level control for adjusting the channel 5/6 output remotely. The remote has a 18 dB adjustment range (-18 dB to 0 dB relative to the gain setting).

Connections

Power/Ground: Two set-screw terminals connect the power and ground cables. The terminals accept up to 4-gauge wire (a 4-gauge wiring kit is recommended). The set screws are tightened/loosened with the included 3mm Allen wrench.

Remote Turn-on: The remote turn-on set screw terminal will accept up to 10-gauge wire. The set screw is tightened/loosened with the included 2mm Allen wrench.

Speaker Outputs: The six pair of speaker outputs’ set-screw terminals will accept up to 10-gauge wire. The set screws are tightened/loosened with the included 2mm Allen wrench.

Signal Input: Three pair of RCA jacks, labeled Channel 1/2, Channel 3/4, and Channel 5/6 connect to line level or speaker level input signals. If connecting the source unit’s speaker wire to the input jacks, use a Speaker-to-RCA adapter or splice speaker wire to an RCA plug. When using a speaker level input signal, it may not be necessary to connect a remote turn-on lead because of the amplifier’s remote sensing function.

Fuses: Three 30-amp ATO fuses protect the amplifier. Another fuse (90-amp minimum) should be placed on the +12V power wire within 18″ of the battery.

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