The selection of a Stereo Amplifier for a home theater system needs to take into account sound quality, functional adaptability and system expandability. Choose according to the room area and speaker sensitivity. For example, the recommended power range for a 10-30㎡ space is 70W-150W (8Ω load), and a large space (>40㎡) requires higher power (such as 100W or more) or bridge mode to increase output. Damping coefficient>100 is preferred to ensure accurate control of speaker vibration and reduce low-frequency tailing.
Signal-to-noise ratio (SNR)>90dB can avoid background noise interference, and high-end models can reach>110dB. Total harmonic distortion (THD)<0.1% is the high-fidelity threshold, and professional-grade products can be as low as 0.003%. Covering 20Hz-20kHz (the audible range of the human ear), expanding to 10Hz-100kHz can improve detail performance, but excessive pursuit of ultra-wideband frequency should be avoided to cause phase distortion.
The Stereo Amplifier needs at least 3 HDMI inputs (including 8K/4K compatibility) and supports eARC to transmit TV audio back. Optical fiber, coaxial, USB-DAC (such as support for DSD 5.6MHz and 384kHz PCM) can meet the access of multiple devices such as Blu-ray players, game consoles, and vinyl record players. Bluetooth 5.0 or above, Wi-Fi (AirPlay/DLNA protocol) to achieve wireless streaming. Multi-room synchronization requires support for wireless audio protocols (such as QPlay or general DLNA standards). High-resolution audio supports DSD direct decoding and MQA rendering. Dynamic range optimization such as AGC anti-clipping function and Hi-Bit 32 audio processing.
Small spaces (such as study rooms/bedrooms) choose compact designs (thickness ≤15cm) with automatic sound field calibration function. Open living rooms require high power and subwoofer pre-output. Movies/games emphasize transient response and dynamic range, and amplifiers with high current output are recommended. For music appreciation, choose a class AB amplifier for a warmer tone, and use MM/MC phono input to adapt to the vinyl system. Link with HDMI-CEC of existing devices (such as projectors and smart TVs) to achieve one-button power-on and signal switching. Support direct connection with streaming platforms (such as Tidal and Qobuz).
Class D amplifiers have high energy efficiency (>90%) and small size, suitable for compact design. Class AB amplifiers have more natural sound and are still the mainstream in the high-end market. New generation amplifier chips (such as TPA3255 and ICEedge) improve efficiency and signal-to-noise ratio, while integrating DSP sound processing. Low EMI design chips (such as TPA3130 series) are suitable for car and compact space. For movies, high power (>100W), multiple HDMI interfaces, and dynamic range >100dB models are preferred. For music, low distortion (THD<0.05%), high-resolution DAC (such as support for 32-bit/768kHz) and analog input interfaces are emphasized.
Focus on comparing signal-to-noise ratio, THD, and number of interfaces, and test dynamic response and tone style in physical stores. Fanless models need to test the temperature rise after 2 hours of continuous operation (recommended ≤45℃). Reserve a subwoofer output interface to support future upgrades to multi-channel systems. Choose a modular design model that can be connected to an independent DAC or post-amplifier to improve performance.