High-fidelity portable Bluetooth headphone amplifier (PCM1794A+TPA6120 solution)

1. Project Introduction
This project is a portable high-fidelity Bluetooth headphone amplifier based on the TPA6120 headphone amplifier and the PCM1794A audio DAC. It uses the QCC3034 Bluetooth SOC and supports SBC, AAC, APTX, APTXHD, and APTXLL encoding formats.
It can be slightly modified to support the USB sound card mode (44.1khz, 16bit). Except for APTX-HD, which is 48khz, 24bit, all other Bluetooth are CD quality (44.1khz, 16bit).
I will dig a hole here. In the future, I will make a portable headphone amplifier based on ES9038Q2M, which supports USB and Bluetooth, and will provide support for higher formats and other lossless Bluetooth codecs.
2. Function introduction
1. Bluetooth playback
2. Switch songs with buttons
3. Adjust volume with buttons
4. Internal filter mode can be selected through jumpers, fast roll-off and slow roll-off
5. Optional pre-emphasis filter, jumper control
6. Charging indication, charging current 1A
7. Specially designed power supply and ground network to minimize noise and crosstalk
8. The maximum output amplitude is 2.24VRMS, which can drive most mid-bottom high-impedance and low-sensitivity headphones.
9. Output impedance 10ohm
3. Other instructions
1. To reduce THD, it is best to use NPO/C0G material for IV feedback capacitor
2. The USB sound card function can be added by replacing the TPYEC female socket (DP, DN, VCHG, GND must be connected, refer to the Bluetooth module data sheet for details)
3. The Bluetooth module uses a finished AL3034 module from Taobao
4. The shell uses an aluminum alloy shell purchased from Taobao (58₤Y4eUda6gIjO£ https://m.tb.cn/h.UfYZiXQ CZ0001 Aluminum alloy shell Aluminum profile shell Aluminum box Aluminum shell Aluminum shell Processing instrument shell 90*44)
Internal motherboard diagram
Rear view