Sorry for my late reply - I'm writing my bachelor thesis and don't have much time for my acoustic hobby at the moment...
My Odroid C1+ and PCM5102A combination is directly connected to the Dynaudio Focus 110A speakers (those are active speakers without volume control -> max amp) thats why I'm using the software volume control. Here are some tests I made and the resulsts...
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I found another post in the forum here with the same problems of noise
I also made some measurements with ARTA (Audio Measurement and Analysis Software) THD datas are in the 0.00x [%] area with 24bit/48kHz and in the 0.x [%] area with 16bit/44.1kHz (1kHz Sinus, max runeaudio software volume, wave files).
Later I set up my own MPD system (Lubuntu/MPD/GMPC) with the Odroid C1+ and PCM5102 configured to play via ALSA Mixer and I had no noise problems. I think there are decoder problems with runeaudio - I had no time yet to look at runeaudios config file. Which decoders are implemented in runeaudio and can be activated/deactivated? And which are the default decoders in MPD? Michael Jacksons Beat It was played in both system about 4 times to slow. Is the Odroid C1+ capable to play 176.4 kHz files? In the S805 Datasheet on page 23 there is no entry for 88.2 and 176.4 kHz frequencies but it plays 88.2 kHz files fine...