Flaws in this chain?

iFi SPDIF iPurifier is for coaxial not optical which OP runs.

Actually, the input is a coax/mini-Toslink combo port. It also outputs both coax and mini-Toslink. Might be a nice inexpensive solution for the OP. I've heard nice improvements using one with an ATV and Chromecast Audio.

@n80 .. there's nothing at all wrong with your system, but if you want an increase in fidelity you have options. First you should be aware that the ATV re-samples all audio to 16/48 then sends the signal on to your DAC. So, if you want to listen to some high res (MQA) via Tidal the first unfold is done by the Tidal software, then the ATV will re-sample your high res back down to 16/48. That is a lot of unnecessary manipulation of the signal and your sound quality will take a hit. I think the benefits of Tidal HiFi is kind of wasted on the ATV. A streamer like the Bluesound Node 2i is terrific if you want to spend $500. If not, you could always go the Chromecast Audio route for a cheap ($35) streaming alternative to the ATV. The CA uses a combo 3mm/mini-toslink optical port so all you'll need is an adapter or a new cable (mini-toslink optical - standard toslink optical). Lifatec makes a good one btw. Best of luck.

But here's a question....why don't device makers, at least high end device makers, include some method for decreasing jitter in the device itself?

Most do in fact.

And as for the Chromecast. Still 'jittery' but less so than the ATV?

Actually, its jitter measurements are rather poor. That being said, the CA sends an unmolested digital stream (via optical) to your DAC, which should clean it up rather nicely. Same with the ATV except the ATV sends a re-sampled (molested) stream to the DAC .. not good.

Re-clockers like the SPDIF iPurifier can do wonders for jittery streams feeding DACs with less-than-stellar jitter reduction, but not so much feeding higher-end DACs which have been engineered to do so.

The Chromecast Audio is by no means perfect, just damn good for $35. A couple of things about using the CA with Tidal on Apple:

1. I don't believe cast is enabled on the Tidal Desktop App yet, leaving you with either Tidal's iOS app or the web player.
2. Safari isn't supported for Tidal casting so you must use Google's Chrome browser if you go this route. Works great.
3. Casting from an iPhone/iPad is quite nice if you have one.

FWIW, IMHO, etc., etc., I would purchase the Chromecast Audio and assess. Then if you feel improvement is needed/wanted try out a SPDIF iPurifier. If the iPurifier doesn't move you .. send it back.

Listener fatigue. Ever experience it? Excessive jitter was the culprit for me a number of years ago. Since that time I’ve paid close attention to eliminating it as much as possible. Never again experienced listener fatigue in my home. DACs have come a long way, yes, but feeding a DAC a low jitter stream can help performance. IMO of course.