jazz drivers

ZuAudio

Not saying it's your answer, but I listen to a lot of jazz on my KEF LS50's with a subwoofer. I like a warm, clear sound as well and am very satisfied, but also have not compared to other speakers. You might also consider adding a tube preamp as it will add some depth and warmth to the sound. 

I had been using an Ayre A7e integrated that I really like to drive LS50s, but there’s no practical way to add a sub, so I’m using an Oppo 205 and NAD M 22 amp with a pair of Velodyne HGS 10s and SMS-1 bass manager. The Oppo front end sounds surprising good, and the Oppo plays Blue-rays as well as being a Roon endpoint -- it replaced an ultraRendu and LPS 1.2.

re: "using an Ayre A7e integrated that I really like to drive LS50s, but there’s no practical way to add a sub..."

Just as a point of clarification, using powered subwoofers with Ayre amplifiers is a common practice.  I've used subs with both the Ax-7e and the Ax-5 for years.