Lee — you are being given a lot of good advice but many are missing the most important element of a stereo system — the speakers.
You mentioned something was missing. Yep. My recommendation is to get a used stereo system on ebay and some good separate speakers.
Yes. Hopefully, all I need will be found together. We’ll see.
Lee — you are being given a lot of good advice but many are missing the most important element of a stereo system — the speakers.
(With the assumption the source material is good, of course!!!)
Next most important is speaker room placement, and how "hard" or "soft" the room is, acoustically, followed very closely by sufficient clean amp power (esp. if you like to listen very loud at all, once in a while, or to music that has not yet been crushed in the "loudness wars".)
If the unit you have now has a headphone output, or better yet an "Aux" output, I'd go get a small separate amp and separate speakers, and hook it to your present unit. This keeps you with "familiar" controls used most often. Parts Express has on sale right now as their "Deal of the Day" (today - move fast!!!):
or for a bigger boomin' system:
https://www.parts-express.com/lepai-lp-168ha-21-2x40w-mini-amplifier-1x68w-sub-output--310-308
These amps' advertised power(s) are highly overrated, but still sufficient for typical listening levels with reasonably efficient speakers (see below.)
Otherwise, see the many recommendations for a small receiver already posted. A good name (Yamaha, Technics, Sony, etc.) is the best bet.
Speakers are all over the place, but for the $$, the Dayton B652's are not bad.
https://www.parts-express.com/dayton-audio-b652-6-1-2-2-way-bookshelf-speaker-pair--300-652 If you miss the "Deal of the Day", try
Listen to the B652's a little off axis: The tweeter has great dispersion, but the woofer gets a bit "harsh" in the upper mids, on axis. Also, if your room is very live (few sound absorbent surfaces) these speakers are not a great choice.
Keep in mind "Hoffman's Iron Law" of bass reproduction: It's bass extension vs. enclosure size vs. efficiency (ability to play at a brisk level with modest power). Basically, if you can manage speakers with 1/4 cu. ft. or more of internal cabinet volume, that tends to help. Better explanation here:
https://sites.psu.edu/speakerdesign/2013/01/24/hoffmans-iron-laws-of-speaker-building/
Use at least 18 ga. copper (not copper clad aluminum) speaker wire, up to 20 ft. per speaker. 16 ga. if over 20 ft. ("Fine" for this little stuff.)
No, I am not affiliated in any way with Parts Express. But I have been a customer for a long time...