3.5mm Interface with Microphone Support Equipped with a standard 3.5mm input supporting a 4pole plug. Compatible with headsets that include a builtin microphone for seamless mobile phone voice calls. Includes an additional terminal connection option for flexible setup. Precision 7Band Equalization Offers a full 7band equalizer with a control range of ±12dB for precise audio . Frequency bands include: 60Hz, 150Hz, 400Hz, 1KHz, 3KHz, 6.5KHz, and 15KHz. Utilizes quality TI or TL074 components for stable and accurate sound tuning. Performance Preamplifier Features a 7band sound equalizer preamplifier with a gain of 5X (14dB) powered by the 4580 classic operational amplifier. Input impedance: 20K for signal handling. Output impedance: 600 ohms for balanced, clean audio output. Balanced Earphone Amplifier Built with NE5532 operational amplifier in a balanced configuration using a 47 earphone driver circuit. Designed to easily drive a wide range of earphone types. Adjustable output level for listening comfort. Practical Applications Ideal for enhancing mobile phone calls with improved microphone clarity and balanced sound. for customizing audio profiles in music playback, allowing tailored equalizer settings for different genres. Suitable for professional and enthusiast audio setups needing precise tone control and the ability to drive various headphones without distortion. This product delivers flexible connectivity, precise sound adjustments, and reliable amplification, making it a powerful addition to any or professional audio system.