The Zapco ST-64D SQ MINI is a compact 4-channel wideband amplifier designed to bring high-fidelity sound to vehicles where space is limited. Built on an NXP Class D solution, it operates with over 90% efficiency, delivering 50 W per channel at 4Ω or 75 W at 2Ω, with the ability to be bridged for 2 x 150 W RMS. This power is delivered with a signal-to-noise ratio exceeding 90 dB and a frequency response from 15 Hz to 30 kHz, ensuring a clean audio signal with less than 0.1% total harmonic distortion. Its miniature chassis measures just 86 x 42 x 133 mm, making it easy to tuck away in small compartments without sacrificing control. You can fine-tune the audio using the variable input gain, electronic crossover, and bass boost controls. The amplifier supports both linear RCA and high-level speaker inputs, the latter of which allows for an auto turn-on feature. For those looking to modernize their setup, the unit is compatible with an optional HD Bluetooth module, providing a versatile solution for audiophiles who need a small footprint but professional-grade performance.