Hello,
I have the same problem on Poco F3. When I turn on Poweramp hi-res output, there is no sound. I tried to turn off DVC, but the sound I get is very low and distorted. I'm using a hi-res converter cable with an audio jack output. I'm pretty sure this is some MIUI update that causes the problems because in the previous android version sound quality was incredibly good. And it's not the only thing with MIUI. While other manufacturers actually keep improving their ROMs, this is very dissappointing that Xiaomi just keep ruining the quality of their software. Before that I had a Galaxy S7 edge. Comparing to Xiaomi, that Samsung is a "plug and play" device with very good quality. I didn't need any converter cable or I didn't need to play with all kinds off deep settings staff to get a good quality audio. I will never buy chinese phones anymore.
