This device is ideal for an Android phone. For Apple phone protocol issues, it is best to control the volume increase and decrease separately by the power amplifier.The Bluetooth device adopts the high-end SA9910_ HD core solution, and the Bluetooth transmission accuracy and distortion are better than CS8675. It currently supportsThe CS8675 of APTX- -HD can support 24BIT 48K format music, but SA9910_ _HD supports LHDC Bluetooth protocol,Can support lossless music format up to 24BIT 96KAt present, many new-generation Huawei mobile phones support the LHDC protocol, and other mobile phones can also support HWA by downloading Haiby music.LHDC protocolAt present, the more popular high-quality Bluetooth audio compression algorithms include aptX/aptX-HD, LDAC, LHDC, etc. The LHDC sound quality is the most idealDecoding chip: This device has an independent HI-FI decoding chip, which is TI's high-end PCM5102A, with a signal-to-noise ratio of 112db;Distortion degree -93db, comes with PLL, Royal Treasure also uses this chip. The sound quality is full and delicate, dynamic, better than ES9018K2MOutput op amp: OPA1612OPA1612 is a high-performance, dual-channel, bipolar input audio operational amplifier launched by TI. Compared with competing devices,OPA1612, which belongs to the TI Burr-Brown Audio product line, can reduce noise and distortion by 60% and 50%, respectively.Bring crisp sound quality to designers. The amplifier can support multiple channels without a significant increase in power consumption to meet various applicationsCompared with other similar competitive products, OPA1612 has the following main features and advantages:Bipolar input can achieve extremely low noise density of 1.1 nV~ Hz and low distortion of 0.0000015% at 1 kHzMachine size: 69*21*72MMPower supply: 5V (The power supply needs to be prepared by the customer, and the power supply can be an Anchuo mobile phone charger, such as the normal type of Samsung S4 S7Mobile phone chargerOutput interface: 3.5 stereo headphone output interfaceYou can directly connect headphones (16-150 ohms), or active speakers, or power amplifiers.