brucehuang55 Hi Everyone, I bought a linear power supply with R-core transformer and did some soldering. I compared the sound quality for different powering source and location. It's just for reference on my own, don't ask me what the difference is. I can only say I can feel. I'm not that sensitive in sound quality like others. I score it from 5 (best) to 1 (worst) for sound quality as follows GPIO on Rpi by linear power supply(5)>P3 on hifiberry digi+ by linear power(4)>mini USB port on Rpi by mobile battery (3)>mini USB port on Rpi by wall-wart charger(1). PS: How to attach images? Thanks for teaching.
Discovery Good news. Now try the 3Xpower supply mod (see link on first page of this thread) and you'll need to extend your range to 6.
