progfu

Good recommendations. I absolutely love Pictures and am always on the lookout for great versions. Although it's not available in high res, I would also add the Solti/CSO 1980 recording to the list.

I'm running the iFi iDSD Micro with a set of HD600s and the pairing sounds VERY good, so the HD650 should be no different. There is more than enough juice to drive them even on the medium power setting. For the money I don't think you can really improve on its quality and flexibility in terms of format support and onboard hardware tweaks.

Hard to say without hearing it. I assume there are no audible ticks/pops? Their absence would not be definitive proof against it being a vinyl rip of course, as it could have been de-clicked at some point. More detailed analysis of the spectrogram might however reveal telltale signs of the different noise associated with vinyl vs tape (for e.g. surface rumble vs wow/flutter), and help identification of the source that way.

There is no greatest single guitarist. It depends on genre for starters, but even then all the greats have their unique qualities. Having said that I'm surprised nobody has mentioned either Allan Holdsworth or Shawn Lane. Both worth checking out for sure, albeit it's not the most accessible music (esp. Holdsworth).

I thought of another I would recommend: the AAM/Egarr recording of Handel's Op. 3 on Harmonia Mundi. https://harmoniamundi.nativedsd.com/albums/handel-concerti-grossi-op-3-sonata-a-5 Wonderful recording. The instruments are so well balanced and isolated. Their recordings of Handel's organ concertos are also excellent, but to my knowledge they're not available as DSD downloads.

Seconded on the Honeck/Pittsburgh SO releases on Reference Recordings. I have their Beethoven 5&7 and SQ-wise it is very impressive.

The AP SACDs also come with additional tracks. Just FYI.

They also recorded an album of Templar chants: Le Chant des Templiers - Ensemble Organum,Marcel Pérès | Songs, Reviews, Credits | AllMusic

Ensemble Organum are great. I particularly love this one (especially the first two tracks): https://www.discogs.com/Ensemble-Organum-Marcel-P%C3%A9r%C3%A8s-Chants-De-LEglise-De-Rome-VIIe-XIIIe-Si%C3%A8cles/release/5449995

The 2496 versions of WYWH and Division Bell are good too.

Tons of great stuff out there. In terms of modern PCM recordings, stuff from Sound Liaison is very impressive and analogue-sounding (there is some jazz there, but also other genres): Sound Liaison Music Shop I particularly like the "After Silence" album from there. Most modern classical recordings are high res PCM, and most are done very well (some use DSD exclusively, like ChannelClassics, but also sell PCM conversions). I find that acoustic music probably benefits the most from high res recording... although this is certainly debatable. Of course there are also many, many high res reissues of classic pop/rock/etc albums out there, but it's quite the minefield. A lot of them are compressed to hell and sound worse than the original redbook masters, or are just simply upsampled from redbook. Research is the key here. Some are done very well however, such as the Steven Wilson remix/remasters of stuff like Yes and King Crimson; I own all of these and they are THE versions to have IMO.

The first which comes to mind would be: Vivaldi: La Stravaganza - Rachel Podger & Arte Dei Suonatori (ChannelClassics) Rachel Podger - La Stravaganza - Channel Classics Records https://channelclassics.nativedsd.com/albums/19503-la-stravaganza-12-violin-concertos

I recently discovered (via this forum) Boganyi's recording of Chopin's Nocturnes: SA-CD.net - Chopin: The Complete Nocturnes - Gergely Bogányi I don't know the works well enough to comment overmuch on the performance (I like it), but the fidelity is absolutely wonderful and the recording native DSD.

The surround mixes are nice and dynamic at least. I often listen to those downmixed to stereo on the fly.

I'm pretty sure the flat transfers on all the blurays and the 24/192 downloads are the same.