Applies to Internal DAC only (Wired Headset/AUX in Poweramp output settings).
Please post your device (with optional ROM/Android version) if Poweramp alpha Hi-Res audio works for it.
If it doesn't work, check this thread:
I would start with the following tested devices. These are devices which were tested by me, usually, it can also work for variants (e.g. Sony Z5 line, not just Premium, etc.).
Samsung S7 Edge (SM-G935FD, Exynos, Android 6.0.1)
Samsung S6 Edge (SM-G925F, Android 6.0.1)
Samsung Note5 (SM-N920C, Android 5.1.1, Android 6.0.1)
Samsung Note3 (SM-N900, Android 5.0)
Samsung S5 (SM-G900F, Android 5.0)
LG V10 (Android 5.1.1)
LG G4 (Android 6.0)