Integrated Tube Amp approx. $2,500

Few people recommending the Willsenton R8, I think its a good amp but not for Klipsch speakers. The Cornwall’s are too efficient for the R8 IMO. You’ll have very little volume range and the remote is too sensitive and is basically useless for the hi efficiency speaker group, just moves too fast to be useful.

Friend drives his Cornwalls with an el-kit 300b amp thast really stunning. For the money its fantastic and well within your burdget including a building service as they come as kits.

another recommended the Decware amps if you can get one they are also great amps.

Finale audio /triode labs used would be fantastic and end game amps. similarly the frankenstine 300b amp.

I second the Willsenton R8. You can buy, sometimes, direct on line, I bought mine as an open box for under 1k delivered. Many option with tube rolling (of course), and operation mode, and simple bias adjust. This was my first "quality" tube amp, There's no reason you can't grow along with this amp. I believe The British Audiophile has an R8 in his stable.

I have the Wilsenton R8 in my living room. It’s been in use roughly two years with zero issues driving my old Dahlquist D30’s and a sub. No noise, original tubes and sounds amazing. A lot of times while listening I forget its price point as I just get lost in the music! 

Not sure how many hundreds you're willing to give, but I second the vote for a Cronus Magnum by Rogue Audio. 

Elekit, TU-8600S 300b Power Amp - nothing better and I see one on the "other site" actually connected to what I believe are Klipsch Cornwalls. This amp always gets incredible reviews.