If you are a music lover having a large collection of CDs that listens a lot to CDs, after reading your posts I suggest getting the SDR 4000SL. I also listen mainly to CD (more than 90% of the time), as the music I enjoy comes mostly in this format and do not see my listening habits changing immediately.
You have an all Spectral system and I have read great things about this CD player. IMHO unless you valuate highly the alternative formats I suggest you should keep your order of the Spectral player and enjoy it thinking you are listening to the best player for your system. There are many cheap DACs with decent performance that you can get for second source if needed.
If we rationalize to much this hobby we will never enjoy it!
I agree with this post and others on this thread in a similar vein.
I have heard hi-res digital, including Quad DSD, but the very best digital playback that I have heard was plain CDs on a dCS Vivaldi and a dCS Rossini. If the Spectral 4000SV is as good as the Rossini on CDs and I would have it, I would count myself a very lucky man. The quality of the playback gear trumps format anytime. The best CD playback will always be substantially better than hi-res on less optimal playback.
In hindsight I have to say -- no offense to anyone thinking and experiencing otherwise -- that one of the absolute smartest decisions in my entire audiophile life was never to give into the hi-res craze. I knew from the start that SACD was doomed as a format, and I have never owned a single SACD. What a relief! Now I see the efforts of those trying to find a great transport for that obsolete format and being frustrated that, for example, the dCS Rossini Player is CD only, because Sony stopped making the technology available needed for SACD transports. I am so glad I stayed on the sidelines and didn't waste time, energy and money on that format! And hi-res files? I think the most recent SOTA advances in CD playback that come much closer to reveal what is actually on those humble silver discs now let us hear the superb musical glory encoded on those discs. Again, I have not heard any hi-res playback that is as good as that, but then I haven't heard hi-res on a dCS Vivaldi or a dCS Rossini either, the machines that have revealed to me the stunning resolution and naturalness obtainable from CD.
Yet I am not interested in hearing hi-res even on those machines. CD is where all the music is found that interests me, and only 1-2 % of the music/performances that I listen to is available on hi-res. And not just quality of playback gear, but most importantly, mastering trumps format every time. Just recently I had an incisive, even ludicrous experience regarding this. At a friend's house we played the album
American Idiot by Green Day, and it sounded very good. A week or two later I wanted to hear that again because of some recent gear changes in that system, and I was shocked. Incredibly small soundstage, very closed-in sound, no sonic impact, subjectively limited frequency range. I was already starting to think that something was horribly broken with the digital playback since the time before (vinyl had sounded good). But then I discovered on the iPad screen that it was the 24/192 version rather than the 16/44 file from the last time. I asked for the 16/44 (CD resolution) file and voila, the old good sound was back! Wide soundstage, very open sound, much broader frequency range, much bigger impact. It was obvious that the mastering of the 24/192 version was a complete screw-up, and the CD-resolution mastering was far superior (the CD also sounds excellent on my system). Mastering trumps format anytime. This ridiculous incidence, admittedly quite non-representative of hi-res as it may have been, only firmed up my resolve to, as I have done until now, never waste any money on a hi-res download in my life!
Even if I buy a Rossini Player sometime in the future, I will leave its high-res capabilities untouched and strictly use it for CD playback. That's where all the music is. And why should I go through all that aggravating pain of proper, optimal computer/server set-up for the unacceptably limited hi-res catalog? And if the CD-only Spectral 4000SV is as good, but saves me a few thousand dollars, I would gladly spend my money on that machine instead!