Putting together first stereo....

I'm a total newbie to home audio, so please excuse the ignorance. So, I spent the last two months auditioning different floor standing speakers and ended up really liking the Vienna Acoustic Beethoven Grands. In the demo room, they were being powered by McIntosh 302s.

I plan on connecting it to a Sonos Connect. My plan was to try to find th McIntosh TC47, since it has a DAC built in, and then maybe going with an older McIntosh amp, maybe a MC7200 to save a little cash. Any comments, suggestions, or thoughts would be helpful.

first of all welcome Chriskchung and do not worry about what we think, most of us have seen it all...

the first thing you need to do is to make sure the speakers will work in the room that you have for them, can you place them out into the room if they need it? Can you audition them at home?

Find this out first as it is the most obvious thing and we move on from there.

good luck

Buying used high end equipment is usually a pretty good buy and good stuff, like McIntosh, is pretty reliable. Same with cables.
Appears you have a good plan for your system. Smart to audition the speakers as you have. All the better if you can hear components in your home. Mac gear I find is wonderful and you will be thrilled for years to come. My only real advice would be that one should choose a system that brings a smile to your face on and off. The best advice will come from your ears. Happy hunting.
Along the lines of what has been said, it is a good idea to focus on speakers first and amp (or integrated) next. Don't worry about the source (Sonos, cheap DVD player, etc) yet. My suggestion is to avoid getting units with built-in DAC. DAC technology has been evolving super fast and it's likely to continue like that. Five years ago we couldn't dream of performance like that delivered for $1k today.

Good speakers and a good integrated amp that match well is indeed a good plan to get going.

When you get to the point of searching for your amplifier, don't forget to use Audio Classics as a resource too. They are the number one resource for used MAC gear and they're friendly and knowledgable.
If you like the Beethoven Grands with the Mac 302 you better stick with that combination. You may not feel the same about the speakers with a different amp.

"Don't worry about the source" is bad advice. The source component is where it all begins. The sound will take on the character of the source no matter what amp and speakers you have.