It is technically more difficult to do an ABX with an analog reference but it can ans has been done.
The results indicate that some digital equipment is not up to par and a lot of analog equipment introduces distortion but Nyquist and Shannon were right - digital representations have quantization and bandwidth limitations but are otherwise true to the original.
Your -q 10 Vorbis sample is fine. I decoded it with foobar and created a time aligned reference sample from my lossless "Dream Theater - In the Presence of Enemies Part 2" rip. I couldn't hear a difference in a quick ABX test. In my opinion the sample is not very demanding. I guess -q 4 or even a lower setting would be fine for this part of the song.Probably your player is causing the problem.
Alex, thank you very much for both listening and giving the links, indeed updating the firmware did the trick.Curiosity: why was it your guess that -q 4 should be sufficient? That is, what do you base your choosing of compression on?