Not satisfy with my first USB DAC, I make another one, with better in design, and more functions. I will take it more seriously and more carefully.
It work well. Though APA2308 is not so good, but it can drive 32ohm headphone pretty well.
Prototype:
Testing:
After testing this one. I don’t use it anymore. ‘Coz the sound from this USB-DAC chip PCM2902E is very “normal”. This one is old version and support USB1.0 only. And the most annoying thing is: it make clipping sound when I start/stop playing a song. I think the suspect is the “silent function” which suspense the DAC when no audio signal is provided, and the chip wake up when audio signal is fed to the DAC.
Then this is a fail project! :(
