Tubes vs Tubeless

Congratulations on getting back into it. I’m older as well... 73, and my system provides great joy to my life. My digital system sounds every bit as good as my outstanding vinyl leg... and if I were doing it today I would abandon vinyl altogether... but I have it. Also, over the last decades, one by one I abandoned solid state for tubed equipment. I highly endorse your approach of focusing on digital and heading for tubed equipment. There is a broad array of tubed equipment at all costs. If like me you like natural and musical sound I highly recommend looking at Audio Research, Conrad Johnson and VAC for solutions. I find tubed electronics with digital and analog legs are equally advantageous. 

You can see my systems under my UserID. 

A well designed tube amplifier will provide enjoyable listening in both cases, as long as its paired appropriately with your Vandy 2CE speakers.  

The short answer is yes adding tubes somewhere can make a big difference, but it really depends what specific improvements you’re looking for and what sound characteristics are most important to you.  Also, what’s your budget and are you looking for new or used?  Your speakers dip down to 4 Ohms so will be a tough load for many tube amps, so you might wanna look at a tube preamp with a solid state amp (as many do here) or a hybrid integrated with tube preamp section with solid state amp.  But it all starts with what sound qualities/improvements you’re looking for and of course budget. 

The 2 variants ( I probably sold a 100x pair back in the golden age , are not a difficult load for a properly designed tube amp - many many Vandersteen dealers carried Quicksilver and got great results.. the 2 acoustic coupler does reward either big output transformer on a tube amp or a high quality SS amp paired with a tube preamp. Belles make just such a wonderful stereo amp.

a tube pre is an much easier beast to feed. Finally if you want an integrated consider the hybrid tube and SS Aesthetix Mimas.