Novice Digital (wired) Question(s)

Going the Apple Airplay route, would you anticipate any appreciable loss in sound quality as opposed to via a cable?  Actually, I’ve been using an Apple TV to more or less do this thru an AV receiver prior to getting the tube amp.  Trouble (?) is that, due to limited inputs on my PrimaLuna Prologue Classic, all such video sources are routed thru the TV, which functions as a switchbox (degradation of signal?). However,... I just happen to have an unused Airport Express lying around.   I guess the only missing link is the DAC then?  One other concern — I’ve digitized a ton of vinyl via Audacity in the form of 16 bit AIFF.  Would this present a problem for a lot of DACs?  Thanks again!

I haven't noticed any loss in sound quality going wireless.

I incorrectly mentioned using a coaxial cable for the output of the Apple TV and Airport Express. I was thinking of something else when I typed that. They do not have coaxial outputs.

I've used the optical output from an iMac, Apple TV3 and Express to systems in my living room, office and garage. The primary limitation on sound quality in the last two isn't Airplay, it's the high level of jitter inherent in the output from the Apple devices. That doesn't mean you can't enjoy the music, I certainly did in all those systems, but if you want better fidelity reducing the jitter is the place to start. 
There are at least a couple of ways to do that, get a DAC (almost certainly a more expensive one) that does a better job of reducing the jitter itself or put a reclocker between the optical output and the DAC.
The Wyred4Sound Remedy Reclocker did a great job in my office system between an iMac and a Simaudio D100 DAC. It made less difference in the living room into a Simaudio D300, a considerably more expensive piece that handled the jitter better on its own. 
In the living room I eliminated the Apple TV as an audio source and now use instead an Arcam rPlay. The Airplay signal goes from my iMac to an 
Apple Extreme router and then via Ethernet to a Wyred4Sound DAC 1. That made for a substantial improvement.
All this to say that I think your effort should be focused downstream of the Airplay signal.

Thanks very much, sfar.  Sounds like a great system....not sure if I’ve got the finances to go that route though.  

I think I’ve got the info narrowed down enough now, re: my own circumstances, to ask a more focused question that’ll help me to decide whether bring digital playback onboard my setup or to stick with it being primarily for vinyl — If I stream music from the iTunes in my Mac via an Airport Express into a modestly priced DAC, (a basic model Cambridge DACmagic or a Schiit Modi 3) and into my system’s integrated amp, can I reasonably expect sound quality as good or better than was the case before this music was ripped into my Mac and was being played as compact discs on a mid-1980s CD player which cost approx. $750 when new?

Jitter may or may not be an issue for you depending on the DAC you use. For me it was a non issue, even with an inexpensive $200 DAC. I read so much about jitter and wondered if it was present in my wireless systems using an Airport Express or Apple TV, even though they sounded fantastic and as good or better than my CD players (an OPPO, an older Denon, and an older Sony). Just to see if I could improve the sound I tried an IFI S/PDIF iPurifier and it actually degraded the sound making it somewhat muddled. I also tried the Wyred4Sound Remedy Reclocker and I could not tell a difference.

I would caution you that there have been reports that some people had problems using the Cambridge Audio DacMagic with an Airport Express.