used Integrated tube amp under $1500 for Klipsch Cornwall III's?

Cayin A88-T used is in your price range. Also, Prima Luna.

Get a Rogue Cronus Mag II, US made, super cust service!Yes I'm a fan.

Quicksilver Integrated.. good, reputable company...there is a nice mint one for sale on USAM..

You might be able to find a used Audio Research VSI 55 for around that. I have one and have used it with my Heresy 1 speakers and it sounded great. I'm currently listening to my Focal electra be 1008 speakers with the VSI 55 and it's sublime.

It would help to know the size of your room, music preference, and how loud you like to listen.. There are a lot of good choices.. If you are in a moderate size room listening at moderate levels, the Coincident Dynamo 34SE MK III amplifier could be really nice.. the mkII has received nice reviews ( Editor’s Choice TAS, Blue Note Award by  enjoythemusic, Positive Feedback ) and the mkIII has some nice upgrades