thanks generally, I will comment to specifics later,
please remember, I don't/won't stream, it's just not for me.
I am the one who started 'upgrade CD to SACD', (I found that from stereophile, below) so I am posting some of what I found online:
https://www.crutchfield.com/S-4hMRMWIbYmp/p_158XA5400E/Sony-ES-SCD-XA5400ES.html
digital-to-analog converters, which employ 12-layer digital filtering and direct DSD-to-analog conversion to deliver superlative SACD performance.
https://hometheaterhifi.com/reviews/audio-player/sacd-players/sony-scd-xa5400es-player/
to criticize the Sony for making a bad mastering job sound bad isn’t right,
the cost, but for just a couple of dollars per recording to make everything in my collection (400 cds) sound so much better
https://www.sony.com/electronics/support/res/manuals/4000/40006911M.pdf
Dual Laser Optical Pickup
Super Audio D/A Converter
CDs are recorded in the PCM format). The DSD format, using a sampling frequency 64 times higher than that of a conventional CD, and with 1-bit quantization
https://www.stereophile.com/musicintheround/music_in_the_round_36
finger-pointing about direct conversion of DSD to analog vs conversion via intermediary transcoding to PCM.
Sony's Technical Background paper spends a lot of words on SACD processing but says little about the player's CD processing, except to describe an 8x-oversampling filter and a noise shaper that result in a 2.8224MHz signal-sampling frequency—the same as that of DSD. "In this way, the SA-DAC presents both CD and SACD signals to the final converter stage in the identical 1-bit/64fs form." The explanation, presumably translated from Japanese, is not entirely clear, but if Sony is implying that CDs played on the SCD-XA5400ES should sound pretty close to SACDs, I think they have a good case.
differences between the two-channel SACD and CD tracks of many discs disappeared, and better CD recordings were revealed as sounding detailed, spacious, and luscious.
July 2020:
It is a multichannel SACD player – the last great one from Sony, massively built
https://www.hifinews.com/content/sony-scd-xa5400es-%C2%A31200
but jitter has always been an issue - until now
With stereo SACD the often slightly edgy upper frequencies, wrought by producers trying to make SACD sound sharper, are buffed smooth without any adverse softening of their impact.
SCD-XA5400ES’s bass is inherently fast and deep.
The balanced XLR output offers a further advance, bringing the 5400ES closer still to XA9000ES quality.
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"In this way, the SA-DAC presents both CD and SACD signals to the final converter stage in the identical 1-bit/64fs form."
Contradicted in writing anywhere?