Pioneer GM-A4704 car audio amplifier 4 channels 520 W A/B

The Pioneer GM-A4704 is a compact 4-channel car audio amplifier delivering up to 520 W total output in a Class A/B configuration. Designed to fit a variety of vehicle interiors, it combines adjustable filtering and automatic input sensing to expand system flexibility while maintaining a space-efficient footprint.

Advantages

This amplifier offers variable high-pass filter control (40–500 Hz) to match speaker or subwoofer characteristics and listening preferences. It provides strong power in a reduced-size chassis for easier installation, and automatic signal sensing that selects RCA or speaker-level input and switches the amp on with the receiver, simplifying integration with OEM or aftermarket head units.

Suitable for

• Upgrading factory car stereos to improve power and clarity
• Driving front and rear speakers in a 4-channel setup
• Systems that require compact amplifiers for limited installation space
• Installations using receivers without RCA outputs (speaker-level input)

Key specifications

• Brand: PIONEER
• Model: GM-A4704
• Channels: 4 (Class A/B)
• Maximum RMS output (total): 520 W
• Filter slope: 12 dB/octave (HPF/LPF)
• Variable HPF range: 40 Hz – 500 Hz*
• Color: Black / Red
• Dimensions (W x D x H): 326 x 215 x 60 mm
• MPN: GM-A4704
• EAN: 4988028340192

How to use

Mount the amplifier in a dry, ventilated location that accommodates its compact size (326 × 215 × 60 mm). Connect speaker outputs to the four channels according to the vehicle wiring and apply power and ground connections following the manufacturer’s installation guidelines. If your head unit has RCA outputs, use them for input. If the head unit lacks RCA outputs, connect speaker-level inputs; the amplifier will automatically detect the input type and turn on with the receiver. Adjust the high-pass and low-pass filters to suit your speakers and listening preferences.

Usage recommendations

For reliable performance, ensure proper wiring and secure mounting, use an appropriate fuse on the power line, and set crossover frequencies starting near the speaker manufacturer’s recommended values (use the variable HPF between 40–500 Hz as needed). Allow adequate ventilation around the amplifier to prevent overheating.