Pioneer GM-A6704 4-Channel Bridgeable Car Amplifier, Class B, 1000W Max

Our review

The Pioneer GM-A6704 is a four-channel car amplifier from the GM Series, rated at up to 1000 watts maximum power and built around Class B circuitry. Its channels can be bridged, and it includes a bass boost plus flexible sound tuning, so you can shape output to suit your speakers and subwoofer rather than accept a fixed factory curve. The steel-look casing and Pioneer's emphasis on high-quality components suggest it is aimed at drivers upgrading a basic head unit setup who want more control over volume and tone.
Before buying, check how your speakers are wired and what impedance they present, since bridging changes the load each channel sees. Confirm your existing wiring, fuse rating and mounting space can handle an outboard amplifier, and decide whether four channels are enough or whether you will later want a separate subwoofer amp. Compare it with other four-channel Class B and Class D amps by channel count, bridging support and tuning options, not by headline wattage alone.