Hardware volume control ( MIXER / XMOS)

Hello Community !

I would like to ask one simple question, which - I hope - will have simple answer :slight_smile:

I just wonder. Does have Hardware volume control ( USB DAC with HW mixer / TOPPING D30 ) influence on audio quality ( THD, noise for example) ? Eg. is it better to keep volume on 100% ?

I asked this because I’m not happy with my headphone ( DENON AH-D2000) driven from headphone amplifier ( TOPPING A30). The sound is not “pleasant” - i have a feeling that there are distortions mainly in mid tones - some instruments sound “metallic” ( sorry for written description of something what we need to hear). So the sound is not painful, but I feel that something is not as expected, looked at technical parameters of my audio chain…
My previous configuration with odroids I2S Hifi Shield+ - without headphone amp - connected to power amp ( DENON PMA-700) did not create that feeling, as mentioned before.

Audio sorces are from volumio 2 on odroid c2, mp3 320, flac 24, spotify, online radio 192k …

Thank You in forward for Your useful thought …

… let me continue the question …
Please look at attached screenshots …
Alsa Mixer shows two volume control : XMOS Clock Selector and XMOS Clock Selector .
if on both mixer the level ( gain) are above -6.00 dB ( 79 %). there is distortion.
From volumio one can control only one mixer at same time.
I have a feeling that mixers are in “serial” connection.

So the new questions :

  • why two mixer ? ( I cannot find any useful information about this via google)
  • how to interpret bars in Alsa Mixer ( volumio)
  • what are the optimal levels ( gain)
  • what does it mean green, white, red colored bars

ThanX in advance :slight_smile: