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The Down4Sound JP43 is a high-output, monoblock Class‑D amplifier engineered for maximum bass performance. With an RMS rating up to 4,300 W at 1 Ω, it’s designed for serious SPL (sound pressure level) systems. Built tough in South Korea, the JP43 includes advanced protection circuitry, dual power and ground inputs, and a remote BT knob for real-time voltage, temperature, and clipping monitoring.

Key Benefits

• Massive Power Output: 4,300 W RMS @ 1 Ω, 2,300 W @ 2 Ω, and 1,300 W @ 4 Ω. 
• Strappable: Can be strapped with another JP43 for up to 8,600 W RMS. 
• Dual 0‑Gauge Power/Ground Inputs: Designed for high current wiring for reliable performance. 
• Advanced Cooling: Internal fan activates immediately to keep the amplifier cool during heavy use. 
• Tunable Filters: Variable low-pass (35–250 Hz), subsonic (10–50 Hz), and phase control (0–180°) for precise tuning. 
• Remote Control: Bluetooth remote knob displays voltage, temperature, and clipping status; “C”‑type power input. 
• High-Quality Components: Tiffany RCA inputs for clean signal path. 
• Warranty Requirement: Requires an electrical upgrade—Big 3 wiring, alternator upgrade, and reserve battery(s)—to maintain warranty. 

Technical Specifications

• Power Ratings (at 14.4 V, 1% THD):
• 1 Ω: 4,300 W RMS 
• 2 Ω: 2,300 W RMS 
• 4 Ω: 1,300 W RMS 
• Frequency Response: 14 Hz – 260 Hz 
• Signal-to-Noise Ratio: 89 dB 
• Damping Factor: > 400 
• Efficiency @ 4Ω: ~94% 
• Input Sensitivity: 0.2 – 6 V 

Filters:

• Subsonic: 10 – 50 Hz 
• Low-Pass: 35 – 250 Hz 
• Phase Control: 0° – 180° 
• Minimum Load: Stable into 1 Ω mono 
• Protection: Thermal, over/under voltage, DC, speaker short 
• Fusing: 400 A total (200 A for each positive input) 
• Power & Speaker Terminals:
• Power: Dual 0-gauge 
• Speaker Output: 4-gauge 
• Operating Voltage: 9 – 16 V 
• Physical Dimensions & Weight
• Dimensions: 15.75″ L × 9.37″ W × 2.64″ H 
• Weight: ~16 lb (based on similar listings) 

Installation & Compatibility

Because of its massive power, an electrical system upgrade is mandatory (Big 3, alternator, reserve battery). 

Use high-quality 0-gauge wiring for power/ground to ensure stable delivery.

Mount in a ventilated area so the internal fan can do its job.

Tune the low-pass, subsonic, and phase settings to match your subwoofer(s) and desired bass response.

The Bluetooth remote gives real-time feedback (voltage, temp, clipping) — use it to monitor and optimize your system.

FAQS

• Is the D4S JP43 suitable for high-output subwoofer systems?
  Absolutely—its strong power handling makes it a great choice for users needing serious bass performance.
• Does the JP43 include built-in protection circuits?
  Yes, it features protection for overheating, short circuits, and voltage issues, ensuring long-term reliability.
• Can the JP43 be used with lithium or AGM electrical systems?
  Yes, it works with both, as long as the voltage remains within the safe operating range.
• Is tuning important with the JP43 amplifier?
  Very—proper gain and subsonic filter adjustments ensure clean power and prevent clipping.