The RetroSound® Quadraphonic amplifier is a plug-and-play solution for adding additional power to your classic car stereo system. The Quadraphonic is a 4-channel amplifier and connects directly to your RetroSound radio delivering 45-watts RMS to all four speakers. Pair it with a RetroSound 8" powered subwoofer for a complete audio system that's a breeze to install. The Quadraphonic amplifier offers an exceptional dynamic range and low distortion with built-in variable high-pass filters for both front and rear channels. Listen to your favorite 60's rockabilly or 80's pop hits in your classic ride with perfect clarity and experience the music the same way you do in your daily driver. Dual gain control allows you to match the input sensitivity to the output of your RetroSound radio for the best possible audio reproduction in your classic vehicle. The Quadraphonic is a Class D (digital) amplifier with advanced circuitry and thermal overload protection. The amplifier's ultra-low current draw, advanced shielding, and compact size of just 7.05” x 3” x 1.65” allows installation almost anywhere, even behind the dashboard, where most amps fail due to electrical interference! A perfect solution for classic cars where space is limited. 4-channel amplifier Full-range Class D digital circuitry 45-watts RMS x 4 channels full-range @ 4 ohms Built-in variable high pass filters Advanced circuitry and thermal protection Directly connects to your RetroSound radio Works with any aftermarket radio with low-level RCA outputs Optional wiring kit available for aftermarket radios Compact size fits almost anywhere Dimensions: 7.05” x 3” x 1.65”(17.9 cm x 7.1 cm x 4.2 cm) For more information, see the user's manual, or browse our support page. Power Output 45 watts x 4 channels RMS @ 4 Ohms Peak Output 55 watts x 4 channels Total Harmonic Distortion <0.2% @ 45 watts x 4 RMS Frequency Response 28Hz-28KHz Signal to Noise Ratio (EIA Rated) >90dB Input Sensitivity 200mV-6.0 volts Crossover Slope 12dB per octave Crossover Frequency 100 Hz Fuse 15 amp ATC Style Dimensions (inches) 7.05” x 3” x 1.65” Dimensions (cm) 17.9 cm x 7.1 cm x 4.2 cm