Zapco ST-104D SQ III Amplifier

ST-104D SQ III Compact 4-Channel Class D Amplifier Overview & Key FeaturesThe ST-104D SQ III is a space-saving, full-range Class D amplifier built for performance without the bulk. This 4-channel amp is perfect for tight installations while still delivering clean, reliable power. With both RCA and speaker-level inputs, it’s flexible enough for almost any system. Fine-tune your sound with variable input gain, adjustable crossovers, and bass boost control—all packed into a compact chassis built for serious sound quality. Features 4-Channel Full-Range Class D Amplifier Accepts RCA & High-Level (Speaker) Inputs Adjustable Input Gain Variable Electronic Crossover Variable Bass Boost Control Technical Specifications Power Output @ 4Ω: 4 x 100W RMS Power Output @ 2Ω: 4 x 150W RMS Bridged Power @ 4Ω: 2 x 300W RMS Total Harmonic Distortion (THD) @ Rated Power: < 0.5% THD + Noise: < 0.1% Signal-to-Noise Ratio: > 90 dB Frequency Response: 15 Hz – 30 kHz ±1 dB Input Sensitivity