jitter

Jitter during recording is different. It shows up as sample errors and that gets baked into the recording. I imagine it would show up as Harmonic Distortion or, based on a quick reading, reduced signal to noise.

What I mean by sampling error is that the value that is written down won't be correct.  For instance if the ADC would record 2.0 V at T0 with a perfect clock, with ADC jitter it might record 1.99997 or 2.0004 instead.

As far as I know it doesn’t produce the same noise side bands that jitter in playback does.

Still, both should be minimized for the best musical recording experience. :)

Jitter is a non-issue solved decades ago! Present day DAC's and streamers are immune to jitter. No need for re-clocking devices, despite what the neurotically obsessed will claim.

No device is completely immune to jitter, but it did get remarkably better after the year 2000.  Any device can be overwhelmed by upstream jitter, and testing with medicore reclockers have shown this.

In general I will say that a good streamer with multi-second buffers should have vanishingly low jitter to add to a DAC's output.

No current DAC can remove jitter that was embedded in the file by the ADC when the recording was made. This is the same as trying to "fix" a recording where the wrong mics were used or poorly placed, or bad mixing, balance, EQ and other decisions were made during production. The latter items impacted many analog recordings beginning decades before digital recording was used.

The best a DAC can do is not add any more jitter and make the situation worse.

One can use tone controls or EQ to improve things, but you'll never totally fix a poor recording any more than you can unscramble a scrambled egg.

I suspect at some point a sophisticated AI could improve things, but even then, it would still be a guess as to what should have been done in the studio years or decades ago.

Hopefully though, we can enjoy the music itself for what it is rather than obsessing over recording quality and technical what-ifs. Good stereos are nice and I certainly enjoy mine, but I can still have a lot of fun and enjoyment listening to a good tune on the car's factory radio. For those of a certain age, think about al lthe great times you had as a teenage listening to the top-40 tunes on your AM radio.

Jitter results from timing errors both in recording and reproduction. Top studios therefore run superior clock sync. In reproduction clocking (Ocxo or rubidium) can make a major difference if the dac allows for it. This particularly applies if dac and server are linked via asynchronous USB. The assertion that modern dacs don‘t create jitter is non-sensical; stanalone quality master clocks alone cost in excess of $7K, those are not contained in $3-5K Dacs.