Looking To Match A Tube Amp With A Pair Of Audio Note AN-K/Spe

I'm the original owner of a pair of K's which I've had for about 9 months. I really enjoy them and they're placed in a 30 x 12 room with a sofa bordering 10' of that 30. I listen about 10-12 feet away. Speakers toed in accordingly. Pushed by a Pass XA 30.8. Preamp is a Backert Labs Rhumba Extreme. I'm overall pretty pleased with this set up but am searching for greater punch and clarity in the midrange frequencies at lower volume levels. I'd like opinions on 2A3 or 300B SET's or EL 34 or 84 push pull as a means of addressing this. Thanks for input.  -Scott