Reading Room: Dedicated Vinyl System, Suggestions

You might want to bring that tube amp up slowly using a variac.

If your going to retain the Music Design SP 2B tube preamp , I would suggest you consider one of there amps. You may want to contact M/Design and see what mods they would suggest for there the SP 2B P/Amp. I would think that replacing the 6922 tubes with a matched pair of NOS and possibly recapping your SP 2B may be something you might want to consider, pending on what Music Design had to say. With regard to speakers, I'm not sure limiting yourself to bookshelf type is any advantage. There are a lot of floor standing speakers that are just as well suited to your room size, with no more of a foot print dimension then the stand used to support the bookshelf type speakers.  You may want to post the question of what other Music Design owners are using for speakers and what was there considerations in selecting the particular speaker. Also it may be a good start to see what speakers were used for review of Music Design Amps and Pre-amps. I agree with oleschool; acoustic treatment will definitely help achieve a higher level of sonics, but I would not disregard the importance of your speaker wire , IC's, P/cords, etc. 

I say this all the time here , room treatment will change the game . I have a 14 x17 x10' dedicated 2:2 and gik just blew the doors off the sound in my setup .. i will digress to other for recommend gear im not to familar with yours 🙏

In a room that size you might not need to worry about a sub.  I think you can find any number of good, stand-mount speakers that provide sufficient low end and will sound more coherent than trying to integrate a sub with the satellite speakers.  I have a room just a couple of feet larger than yours, and I've found a decent pair of bookshelf speakers to be more than enough in terms of bass (and sometimes even too much).

Just a thought,Scott

Lots of options. My system is in a room that size. Have a look. Sort of depends on budget and goals. Provide more info and suggestions will follow, from lots of directions.