Didn't really do very much. For example I'm listening to Kurt Cobain on 'Polly' via Qobuz at 96khz flac and his voice just doesn't sound right. Voicing seems off, lacking in tone, and actually his accent isn't as marked. In fact it's clearly audible on the entire album how his voice doesn't seem right. I like the detail I'm hearing but the voicing seems skewed, thats instruments and vocals. Anyway I guess this isn't the forum for subjective discussion on sound which we all perceive differently!
In the last sentence You are absolutely right. I have that album on first press vinyl, sacd, flac and on reeltape. I have the D90’s MQA version. The sound issues You are describing is for certain that You have poor, low quality parts in Your system. The D90 DAC sounds almost as good as my Esoteric X-05 playing flac visavi sacd. Do not forget the rest of the soundchain. My speakers are Infinity IRS Epsilon driven by three Krell poweramps and Krell preamp. Cables are high quality and I have DC blockers and iFi purifiers. I have DACs that are way more expensive, Bladelius, Hegel, Schiit, Pioneer that can not compare with the D90. Only the Esoteric can.