Improvements in Hi-Fi Class AB Amplifier Design

High-fidelity (Hi-Fi) audio amplifiers are essential in both professional and consumer applications, where sound quality is determined by factors including frequency response, signal-to-noise ratio (SNR), and total harmonic distortion (THD). This paper presents the design and implementation of a Class AB audio amplifier optimized for reduced distortion and precise signal control. The proposed system incorporates frequency splitting to enhance power distribution, a highstability power regulation system to stabilize voltage fluctuations, and a digital volume control interface using SPI communication for accurate adjustments. By focusing the main amplifier's bandwidth on mid and high frequencies (100 Hz - 25 kHz) and redirecting low frequencies to a dedicated preamplifier, the design achieves a balanced and dynamic audio output. Experimental results confirm that the amplifier delivers at least 50 W per channel (55 W measured), without noticeable distortions or noises, making it a viable alternative to high-end commercial amplifiers.