Just want to share my experience with Topping E30 that I bought the same day it went live on HPZ and got it the next day.
There is no power supply so I used my old LG G5 charger. There was a horrible crackling and popping sound in both DAC and preamp mode, I called HPZ and they agreed to return it. This was actually a power supply issue and on changing the PS to Bose speaker charger, the DAC has been working very well.I later saw that the LG charger outputs at 5v and 9v both.
if you face SQ issues, try changing the power supply
There is no power supply so I used my old LG G5 charger. There was a horrible crackling and popping sound in both DAC and preamp mode, I called HPZ and they agreed to return it. This was actually a power supply issue and on changing the PS to Bose speaker charger, the DAC has been working very well.I later saw that the LG charger outputs at 5v and 9v both.
if you face SQ issues, try changing the power supply