Whether your going from your laptop to the Marantz or your going from the laptop to the Oppo,.
Have you turned the volume up on your laptop ? And did you set up the devices properly on the laptop in the sound control panel ?
I have the volume at maximum on the laptop including volume on the Amazon Music app.
In the control panel under sound, I had set it from DVD quality to 16/176 but must have forgotten to hit the apply, I went back in and saw it was at the defult setting of DVD.
Set it back up to 24/176. Sounds like it should now.
Earlier I said I was hearing some distortion/harshness in the upper frequencies , I listened to the same CD track through HEOS, I clearly picked it out as an acoustic guitar playing in the right channel. After resetting the sound quality in the control panel, I can hear the same acoustic guitar playing in the right channel of the Amazon Music app.
I have read in a number of places that using a USB 2 audio connection over hdmi, the audio quality improves since it bypasses most or all of the pc's circuitry. So going on this, I will have to keep attempting getting my usb 2 audio to work. I have oppo's 1st version of this usb installed, for some reason, my laptop will not install oppo's last to versions after downloading them. Seems the 1st version should be enough to get me going via USB connection.