According to the Klipsch site the cornwalls sensitivity is 102 dB @ 1 watt/meter. This will get loud with not much power at all. I suggest putting more emphasis on tonal balance, transient response etc, rather then the output power.
There are a few amps that have tube / output transformer combinations that have earned very good reputations. Most amps with the EL84/6BQ5 output tubes have very good reputations. These might be the Dynaco Stereo 35 power amp, SCA 35 integrated amp, several Eico and Scott amps, Sherwood and Stromberg Carlson. These will be in the 10 to 15 watts per channel power range but will sound very good. These can get those speakers of yours up to 109 dB peak output leaving you with a 3 dB buffer against clipping. That's pretty loud. For a little more power but still in the same tube family is the 7189 tube.
If you still need to rock out look for something with EL34 / 6CA7 outputs. These will tend to be in the 25 to 40 watts / channel range. They too sound pretty good but there seems to be a consensus (at least as I read this forum) that the EL84 types sound sweeter if they have enough power for your speakers. One note here - the Dynaco Stereo 70 is perhaps the most famous of these amps. In stock form it has some performance deficiencies that must be fixed to get the most from it. If you go that way in a stock unit, expect to need to modify it. Those can range from a few dollars (a mod that is not considered well among those on this forum - i know cause I am an advocate of it have have received some comment on it) to a few hundred for new power transformer and circuit board and power supply upgrades. In the same power output category is the 7581 or the 7868 output tubes. These include the Fisher 400 and Eico Stereo 70.
If you want even more power then you are looking at 6550 or KT88 outputs. There are lots of amps in this category as well. Among them the Dynaco Mark III and the Citation II and the McIntosh 275 among others. All have fine reputations. These are in the power output you mentioned.
There are other output tubes that are well respected however I am not familiar enough with them to comment on them here (so 6L6 etc lovers please excuse their absence).
This is just a short list. Understand that with any tube amp you need to make a choice, go vintage and sink some money into upgrades to make it more reliable, or go new and perhaps spending more then you might have expected. There is also the possibility of purchasing new from China, which has a mixed reputation for long term reliability on this forum.
The bottom line here is that you need to be happy with what you are hearing. You have very sensitive speakers that (I believe) could easily put any deficiencies in the amp on glaring display. A wrong choice could make the system tiring to listen to. A good choice will send you to sublime listening pleasure.
Good Luck
Shelly_D
