Small but complete. Little Sparrow is a Bluetooth decoding headphone amplifier with complete digital and analog circuit architecture. Use Qualcomm CSR8675 front-end solution, support APTX-HD and LDAC high-definition Bluetooth encoding, up to 24bit/96khz. The use of dual audio crystals in conjunction with the CS43198 decoding chip is completely different from the audio-free crystal oscillator scheme or the digital flush alignment scheme, and there is no local SRC processing to avoid the degradation of digital audio signals by secondary SRC outside the mobile phone. Although the CS43198 has a digital volume control function, it still uses a traditional volume potentiometer to avoid the dynamic compression problems caused by the use of digital volume. And the signal selection function is designed to allow users to adjust the sense of hearing. Unlike most portable Bluetooth amps on the market, we did not use a DAC chip with amp function, but instead used a dual op amp as the amp to directly drive the headset, and provided an independent positive amplifier for the op amp. Negative power, this is the real headphone amplifier, users can also get a different experience by replacing the op amp. It is controlled by the MCU chip, including various settings and relay protection of the switch, low-voltage battery protection, and a 1100MAH Sony polymer battery, which can provide a 10-hour long-distance voyage. Volume: 7*5*2CM