Zapco - ST-4X DSP III - Class AB, 4-Ch, DSP, optional HD-BT Power 2Ω: 4 x 90W, 4Ω: 4 x 65W

The Zapco ST-4X DSP III merges Zapco’s legendary Class AB sound quality with advanced DSP control. Offering 4 channels of clean amplification with built-in tuning flexibility, it’s perfect for high-end OEM integration or compact SQ systems. Optional HD-BT connectivity adds wireless tuning and streaming functionality.

• Model: ST-4X DSP III
• Channels: 4 (Full-Range, Class AB)
• Built-In DSP: 32-bit / 96 kHz Digital Signal Processor
• Power Output:
 • 90 W × 4 @ 2 Ω
 • 65 W × 4 @ 4 Ω
 • 180 W × 2 @ 4 Ω (bridged)
• Total Harmonic Distortion (THD): < 0.5% at rated power
• Signal-to-Noise Ratio: > 90 dB
• Frequency Response: 15 Hz – 30 kHz ± 1 dB
• Input Sensitivity: 0.25 V – 5 V
• DSP Processing:
 • 31-band parametric EQ per channel
 • Adjustable crossover slopes (6–48 dB/oct)
 • Time alignment and phase control
 • Input and output level mixing matrix
 • PC tuning software via USB connection
• Inputs: RCA and speaker-level inputs
• Outputs: RCA preamp outputs for system expansion
• Optional Accessory: Compatible with Zapco HD-BT II-A (High-Definition Bluetooth Module)
• Protections: Thermal, over-current, short-circuit, DC offset
• Construction: Compact chassis, precision Class AB circuitry, and high-efficiency cooling design
• Dimensions (chassis): ~ 160 mm × 58 mm × 300 mm
• Overall Dimensions (with end caps): ~ 160 mm × 58 mm × 325 mm