Ayre KX-5 preamp with V-3 amp

If you want to stay with Ayre, sensible given your other gear. I would reach to their newer products. The V-5 is a clear step up from the V-3. The K5xe is a great pre but, mated to a V-3, it might not be any better than the AX7e integrated which you might find for not much more than a V-3. The V-3 is fine in its own right but is bettered by the later models.

BTW, I highly recommend upgrading your QB-9 to the Twenty version.

Oh, wow, might as well just use all that John Curl designed gear! Charles Hansen used to publicly acknowledge Curl’s influence on his circuit design, they were quite friendly on some of the forums. Could be interesting to compare the K5-xe and JC-2.