i saw this video
video
why when he connect the YX5300 UART he dont connect any resistor? i saw that
"Power supply can be 3.2 ~ 5.2VDC"
What resister are you referring to?
There is no resistor mentioned in this YX5300 module description: http://geekmatic.in.ua/pdf/Catalex_MP3_board.pdf
Just plug in headphones, serial and power/gnd.