Summary:  The audio amps appear weak.  Fade badly probably due to chip temperature.    But even at the begining it was not ever going to shake the windows out of the frames.

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Research Links

• AE: DIY Bluetooth Speaker Kit Electronic LED Music Spectrum MH-M18 Dual Channel Soldering Practice 3W Speaker 8002 Amplifier DC5V

Documentation

• 56DZ.com:  Zip Documentation Archive  – use GFRT as password from paper sheet that came with the kit
• LocalCopy:  WK-56-90 Sound Box Zip archive
• Driver amp board schematic pdf
• LED Board schematic pdf

DataSheets

• Mix2018 Audio Amplifier
• STC15W401AS series MCU PDF

 

   

The audio chips had a big plated through hole to act as a heat sink which I did not solder to. This may have been responsible for the audio fading rapiding and badly.  The fade was so bad that I'm skeptical it would ever work very well.  One channel had problems and did not pass any audio at all.  

 

  

  

• JL or “pi”  == JieLi)
• Duck: jieli 55f4
• jielie – Chip markings explained
• zh-jieli.com
• G: jieli bluetooth chip data sheet
• JieLi-BlueTooth-Chip-Representative-AC6925ADatasheet.pdf
• Duck: jieli bluetooth chip data sheet
• JL AC6955F Bluetooth 5.1 audio module + SD card playback – Schematic JL AC6955F Bluetooth 5.1 audio module + SD card + tp4054 battery charger
• EEVblog Electronics Community Forum:  JieLi BlueTooth Chips