Best preamp fpr AR Classic speakers?

I need your suggestions for a dedicated music set up I am finally getting around to. Here's what I have so far:

AR Classic 26 speakers (88 db, 4ohm)
Nakamich1 PA 5 mkii amp
Denon 3810 for playing CD's

Budget is limited (less than $2K). Looking at Pass X-1,Musical Fidelity, Krell etc. Never had tubes but could be open to that.

The AR's tend to be a little bass-shy but uppers and mids are terrific.

I listen to blues,jazz,rock mostly.

Thanks for your help.

Vincent