Features

Overview: The Memphis Car Audio SRX300.4 is a Class AB Street Reference series 4-channel amplifier for driving two pairs of speakers (4-channel), one pair plus a subwoofer (3-channel), or two subwoofers (2-channel). The amp features a compact aluminum chassis with textured heatsinks and LED accent lighting. The SRX300.4 comes with two speaker-level input harnesses, spare fuses, and mounting hardware.

Output Power: The SRX300.4 has the following output:

• 50 watts RMS x 4 at 4Ω
• 75 watts RMS x 4 at 2Ω
• 150 watts RMS x 2 at 4Ω bridged

Controls: The amplifier features independent controls for the front and rear channels on the end panel:

• Sensitivity: The Sensitivity (or Gain) Control helps you match the amplifier to the output of the source unit. This adjusts the amount of signal required to drive the amplifier to full output. The amp will accept low level signals between 100mV and 6.0V, and high level signals between 400mV and 12.0V.
• Crossover Mode: The crossover has a slope of 12dB per octave. Using the 3-way switch, you can set the crossover to one of the following modes:
  • High Pass: The variable high pass filter sets the lower frequency limit of the amplifier's output. The crossover point can be set between 50Hz and 1000Hz.
  • Low Pass: The variable low pass filter sets the upper frequency limit of the amplifier's output. You can set the crossover point between 30Hz and 250Hz.
  • Full Range: The internal crossover is disabled, allowing the signal's full frequency range to pass through the amp.
• Bass Boost: The Bass Boost increases the bass response by 0dB, 6dB, or 12dB at 45Hz. You can select the amount of bass boost using the 3-way switch.
• Input Mode: A 3-way switch lets you set the input mode to 4-channel, 3-channel, or 2-channel. In 4-channel mode, two stereo RCA cables are connected to the RCA input jacks. This allows you to maintain front-to-back fader control from the source unit. The 3-channel mode drives the amplifier with a stereo front signal and a mono rear signal. This mode can be used when bridging the rear channels to drive a subwoofer. In 2-channel mode, all four channels are driven by the front channel input, and fader control is lost.

Protection Circuitry: The amplifier features built-in circuitry to protect the amplifier against overload, short circuit, overheating, and reverse polarity. A Protect ("PRT") LED on the side of the amplifier will glow red when the amplifier shuts down due to any of the above causes.

Connections: The SRX300.4 has the following connections:

• High Input: The amp includes two 12" 2-channel speaker-level input harnesses for connecting the amp to a source unit that doesn't have RCA preamp outputs (such as a factory radio or factory amp). You should splice the left and right speaker outputs from the source unit to the harness wires and plug the harnesses into the amp's 5-pin Molex connectors.
• Low Input: The amp features two pairs of RCA jacks for connecting the amp to the source unit's preamp outputs via an RCA patch cable. Inputs for front and rear channels are provided. If the Input Mode switch is set to "2CH", only the front RCA jacks are needed.
• Fuses: Two 25A ATO (blade) fuses are installed in the amplifier, giving the amplifier a 50A fuse rating. Two spare fuse are included, as well. You should also install a 50A fuse on the power wire within 18" of the battery.
• Power/Ground: The amplifier features nickel-plated screw-down terminals for connecting the power and ground wires. The nickel plating resists corrosion and maximizes power transfer. The power and ground terminals are 1/2" wide, and will accept bare wire or spade connectors. Due to the 50A fuse rating of the amp, an 8-gauge amplifier wiring kit is recommended. A set-screw terminal for the remote turn-on lead is also provided. The power/ground set screws can be tightened/loosened with the supplied 4mm Allen wrench, while the remote turn-on lead set screw uses the supplied 2mm Allen wrench.
• Speaker Output: Nickel-plated screw terminals are also provided for connecting the speaker output wires to the amp. The terminals are 5/16" wide, and will accept bare wire or spade connectors.