Your device supports Hi-Res audio _output_* (at least 24bit, at least 96khz sampling rate), but Poweramp v3.0 alpha doesn't support it?
Request the support here!
Please provide (requests without these items will be deleted):
ROM version (Android version, stock/OTA/Custom ROM): /system/build.prop file or adb shell getprop output
Why do you think your device supports Hi-Res (link to device features, etc.)?
For recent Poweramp builds, screenshot of Set