CLASS D

Fosi V3 or V3 Monos with 48 volt power supply.

Yes I have V3 and suspect it would do nicely with Klipsch. 

Rogue Sphinx V3 with Gold Lyon tubes.

I have ICEpower 250ASP units and thought they were a little dark and laid back, a lot like Parasound's Halo line.  I am not currently using htem but about to put them back in for surrounds.

Atma-Sphere Class D would work just fine for your application.

Iwin +1

Iwin +2

Have you considered bi-amping? I haven't heard your speakers bi-amped, but I've recently heard fantastic results bi-amping Q Accustics and Sonus Faber. 

Cornwall 4’s mated to AGD Audion Mk3 monos and fed through a Primaluna EVO 400 tube pre has worked very well for me especially after seeding the monos and the tube pre with Audio Magic M2 fuses. The DAC is a Holo May KTE. Will probably also fuse that with an M2 eventually.

I appreciate it. I already own a Crown class D amp. Don’t these little amps from China all sound about the same?

If it's a Box Woofer Klipsch. You NEED JUICE to move that Woofer. A flea bag Tube Amp is only good on the Horns. I ran Orchard Audio Ultra's on my Cornwall IV's with a Tube Preamp (BAT VK50-SE, Black Ice Audio F360, and my favourite Black Ice Audio Aries Headphone Amp/DAC/Preamp. 

Or an active sub with the high level hookups.

Buckeye Amps. You're welcome.

Another vote for AtmaSphere.

Bel Canto. John Stronczer has class D dialed in. The E1X integrated is all you need. 

Orchard Audio Starkrimson monoblocks work well with my Devores, which don’t really need the power but come alive with it.  

+1 on the Orchard Audio Starkrimson monos !!

Another vote for AGD. I have the Tempo. 

Agree Ralph's Class D amps would be a great companion.

Take a look at the CODA S5.5, if you'd like Class A to consider. 50WPC in Class A, much more in A/B, and 100 AMPs current delivery. I've not heard them with Klipsch speakers, but many times with Volti Razz speakers where they were a brilliant pairing. I have one that happily drives: Buchardt Audio S400 MKIIs, Clayton Shaw Caladans, Thiel CS 2.3s, and even old school Infinity RS Kappa 7s

If it’s a Box Woofer Klipsch. You NEED JUICE to move that Woofer.

+1 @rajugsw - although the horn’s tweeter and midrange can easily handle flea watt amplification, the less than efficient (difficult impedance curves) woofers are tougher to control without adequate power

For “warm” non- tube amplification, maybe a GanFET like AGD and Atma-Sphere or a sliding bias amp like Krell. 

@moose89 - are you open to hybrid amps with tubes?  

Of course @kennyc . I’ve put Orchard Audio Ultra’s on the Woofers of my Cornwall IV’s and a Black Ice F100 with 6550 Tubes and even the big KT170’s. Excellent results. You get the fast articulate Bass of Class D while getting that "warm & gooey" mids and high’s that horns with Tubes are known for.