Need suggestions for streaming files to my stereo

Apologies if my description made the Pi solution sound intimidating. Here are the parts you need if you go this route and want to use a Hifiberry Digi+ to connect the Pi to your stereo's DAC using either TOSLINK or SPIDF.

- Raspberry Pi 3B (other versions may work, but depending on the version, you could lack sufficient processing power to stream 192/24, or you may lack desired network capabilities, etc. With the 3B, you will have no trouble)

- A 5V DC power supply with a micro-USB connector that supplies at least 2A of current (I use the iFi Power 5V version, which includes a micro-USB tip)

- Hifiberry Digi+ or Digi+ Pro (it will come with all of the small parts necessary to connect the Hifiberry board to the Pi -- no need to buy any others assuming you use one of their enclosures). 

- An enclosure for your Pi/Hifiberry device (Hifiberry makes several that are sized properly, https://www.hifiberry.com/shop/ , although the cases can also be purchased from other sellers, including Amazon I believe)

- A micro-SD card, which you will use to install an operating system on your Pi (the OS will be used to play music). The RPi 3B has a micro-SD slot, so once the OS is installed on the card, you will insert it into the slot and simply leave it there.

The hardest part will be installing the OS on your micro-SD card. Follow these instructions:
https://www.raspberrypi.org/documentation/installation/installing-images/

If you have decided to get a Hifiberry board in order to add TOSLINK/SPIDF outs, be sure to choose an OS that supports it. I know that Moode and Roon both support it. I can't say for sure whether other OSes support. 

If you go with Moode, here is documentation to configure it to work with the Hifiberry once it has been installed on an SD card.
https://www.hifiberry.com/build/documentation/moodeaudio-installation-and-configuration/
Be advised, however, that this documentation makes no mention of configuring the RPi to work on your network. My advice is after completing Step 8, wait a few minutes for your Pi to reboot and then return to Steps 4 and 5. This time, Instead of clicking "Audio" (step 6), click "Network" and make the necessary changes so that the Pi connects properly to your network. At this time you can also disable unnecessary components (e.g. Bluetooth adapter, wireless network adapter if you are connected with ethernet cable)

I hope I demystified this solution somewhat. Again, good luck!

Lastly, @prpixel is absolutely correct that there are also many other small kits available that can serve the same function as the Pi, if this still sounds intimidating.

Autre,

I think you misunderstood my previous post.  I wasn't advocating against using LMS, I was just pointing out that it is not a long term solution.  And, with only $35 invested in a CCA, it's not really that big a deal if it stops working in 5-10 years.  I'm sure by then, you'll have saved up enough to move on to something else.  LMS can run on just about any computer running Windows, MacOS or Linux.  So, if you have an old laptop or PC sitting around the house, put it to use.  After all, if you don't like it, the most you loose is a few hours of your time.

Let me explain what the SlimServer is.  It's a Server, maintained by either Logitech or Sean Adams, that hosts. mysqueezebox.com.  Mysqueezebox.com allows Squeezebox users to do two things.  First, it allows you to use you Squeezebox for Internet Radio, Pandora, etc without having to install LMS on a local computer; it stores your account info.  Second, it provides the clock information for the clock screensaver.  So, if Logitech were to shut it down, then you would need LMS running on a local computer to use these services.  I believe that most Manufactures of Streaming devices maintain a Server to store basic account info.  I know that Sonos, Google, Amazon, Play-Fi, Hoes and Bluesound all do.  At least, all the different units that I've tried/own do.  Since the CCA would only be using LMS to "serve" your music library, then you'll never have to use Mysqueezebox.com.

On a side note, you don't have to use LMS to "serve" your music.  There are many other software choices such as Kodi, Plex, BubbleupPNP, etc that do the same thing.  It all just depends on your comfort level with setting them up.

Finally, thanks to Thunder240 for providing the instructions for the Raspberry Pi.  You don't actually need the HifiBerry card because you will not be plugging any audio devices directly into the Pi.  Complete kits can be purchased on Amazon for $70 with a 32GB memory card.  You will also need an external USB drive to hold you music files.  A 1TB drive can be purchased for around $60.  Keep in mind that the Pi only has 1GB Ram and is pretty slow, but perfectly fine for a server.  A Intel NUC5CPYH kit or a Gigabyte GB-BXBT-2807 kit with 4GB Ram and 128GB SSD or 1TB mechanic drive can be had for around $200.  You would have to add an OS.  Windows 10 can be purchased on Ebay for about $60.  If you want to go with something a little bigger, then a  HP ProDesk 400 G3 Mini - I3 6100T Reburb can be purchased for less than $300 with Win10 and 500GB drive though I really recommend an SSD.  

I hope then Thunder and I are not confusing you with all the options,

Thanks for explaining that bit about LM. The options are great, and to be honest Prior to this post zi didn't think it would be possible to put together something for such a paltry amount. Sure am glad I posted the question!  The Raspberry option sounds pretty good. 

One last wuestion (for now). Any preferences for the OS for the Raspberry (if I understood this correctly), JRiver, etc...?

You'll have to use a Flavor of Linux that supports ARM CPU's.  As for which one to use, I'll defer to thunder240 to answer that question.  Also, JRiver is Playback Application, not an OS.  JRiver is available for Linux.  If you're planning on using the Pi plugged directly into you audio system, you'll need the HiFiBerry kit.  Then, you would use an Application like JRiver to play music.  Many people swear by the Roon Player, but it's pricey at $119/yr or $499/lifetime.

If you're planning on just using the CCA as the Audio source, then all you would need is an Application like Plex, Kodi, etc to "serve" the music files to the CCA.  If you go this route, once the Pi is setup, you can run it headless; without a monitor.  You would use another computer, or tablet/smartphone, to control the Pi remotely for occasional maintenance, changes to settings, etc.  My Music Server is actually mounted on the wall right next to my router.  I use my main computer to control it remotely for occasional software updates, maintenance, etc.  Also, I use the LMS web-portal to control my Squeezebox Touch, which by the way, is sitting right next to me; it's easier than using the players own interface. To use the other Squeezebox devices located throughout the house, I use an app on my phone.

Thanks to all of you I now have a grasp of how the system works. Now that I understand it better, I thought of a few options. Please let me know what sounds best (or if it's even viable). 

1. Use a 7 year old Dell laptop that I forgot we had. Works fine but so may want to upgrade the wireless and Bluetooth. Drawback is if I leave it running for extended periods, it heats up and the fan engages every few minutes. 

2. Use a tablet connected to an external HDD that holds the music files?

3. Stick with the Raspberry option.