I just registered to this forum to say that the NW-A100 (A100 series) / ZX-500 (ZX-507) series are absolute garbage for the price you pay.
Over the lower tier A series like the A40 and A50, you lose:
-Sound enhancements/features/options that are no longer there or are not customizable
-INABILITY TO CREATE OR EDIT PLAYLISTS? IS THIS A MUSIC PLAYER????? Their solution is "Bookmarks" which cannot be exported or backed up!
-Native music player just SUCKS, you cannot even scroll down on a list properly.
-Battery is okay, just similar to any phone out there but VERY slow charging.
-Inability to play bit-perfect mode. Question here tho, is bit-perfect required for MQA? If so how can they state they support MQA?
-NO android app supports the internal DAC. JetAudio, USB Audio Player Pro, PowerAmp, Onkyo HF, Fiio, etc. NONE, more above this below.
I contacted the developers of a few of these apps and general android devs, they all told me the same it's Sony's fault on how they came about with the OS. A person close to Sony and the dev team mentioned this to me:
" Sony has implemented is a proprietary upscaling across the board to 192 kHz / 32-bit, this will not be reflected in the software logs of the third-party software logs as the S-Master HX™ chip performs the up-scaling before converting into analogue signals.... An implementation that is universal and fuss-free, however, does not offer Bit-Perfect. I have provided feedback to the Sony team who are now sticking to this implementation which I can understand why. "
This is what I get from the audio policy configuration:
<mixPort name="primary output" role="source" flags="AUDIO_OUTPUT_FLAG_PRIMARY">
<profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
samplingRates="48000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
</mixPort>
<mixPort name="offload output" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT|AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD">
<profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
samplingRates="44100,48000,88200,96000,176400,192000,352800,384000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
<profile name="" format="AUDIO_FORMAT_PCM_32_BIT"
samplingRates="44100,48000,88200,96000,176400,192000,352800,384000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
<profile name="" format="AUDIO_FORMAT_DSD"
samplingRates="2822400,5644800,11289600" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
</mixPort>
</mixPorts>
TL;DR
Absolute trash of a DAP, it just cute and useful if you want a generic music player with hardware buttons and support for streaming apps. But for that price?! Nah, thanks!
Message for Sony:
Revert back to your proprietary OS, better battery life, MORE features and BETTER support.