Brand NEW! Including 90 Days USA Factory Warranty. The Dayton Audio SPA500 Subwoofer Amplifier delivers the efficiency of a Class-D design, without compromising audio quality and reliability. We stand behind our products and our warranty is a demonstration of our commitment to quality and reliability. Key Features High power Class-AB output stage for clean, controlled output Patented tracking downconverter power supply for high efficiency Toroidal power supply transformer Low frequency parametric EQ allows you to boost or cut to custom-tailor sound Advanced soft clip circuitry improves headroom and protects woofers OTC #153 (Optimized Thermal Circuit) protects amplifier from potential heat damage Hercules heat sinks dissipate and control heat for extreme reliability One of the most technologically advanced subwoofer amplifiers on the market today! The Dayton Audio SPA500 subwoofer amplifier is based on a state-of-the-art Class-G circuit topology that combines the proven high power, high fidelity characteristics of a Class-AB amplifier with a patented tracking down converter power supply to achieve an operating efficiency up to 86%. You get the efficiency of a Class-D amplifier without compromising audio quality and reliability. The Class-AB output stage provides the clean and low-distortion sound that audiophiles demand, without any of the instability problems that plague other high-efficiency amplifier designs. This American-designed and engineered amplifier uses patented circuitry that continuously tracks the input signal to modulate or control the voltage available to the output stage. This "tracking" capability delivers the exact amount of power based on demand instead of constantly keeping it in reserve, so the output stage only draws the amount of power that is required at any given time. Less energy is wasted as heat, and more power is available for the subwoofer driver. With its enhanced thermal management, the SPA500 is an upgrade over previous models?making it a nearly bulletproof amplifier choice for today's demanding HT audio and music playback applications. Specifications: ? Rated power output: 273 watts into 8 ohms, 540 watts into 4 ohms with 0.92% THD (based on one-third power duty cycle) ? S/N ratio: 98 dB (A-weighted) ? Low-pass crossover: 30 - 200 Hz, 24 dB/octave ? Input voltage: User switchable 115/230V (Euro cord available) ? Dimensions: 11-15/16" W x 11-15/16" H x 5-1/4" D; Cutout dimensions: 10" W x 10" H. - All international buyers are responsible for all tax, duties and/or customs fees.