Cube Audio Nenuphar Single Driver Speaker (10 inch) TQWT Enclosure

The Klipsch is a high sensitivity speaker yet may possibly  benefit from more power due to crossover design and big woofer control. The crossoverless,   very easy to drive load Nenuphar is a different animal. S.I.T. 3 amplifier and Nenuphar is considered to be a splendid pairing. As they say, "horses for coures".
Charles

Since we’re talking about first watt amplifiers that may provide a good match, I’d just like to mention that the F4 doesn’t get enough attention.

25 watts, zero negative feedback, and no gain stage to modify the sound of your source and preamp, all it does is provide current. A very simple circuit. If you’ve got quality upstream components and enough voltage from your pre/source, it is just fabulous. On my Coincident PREs, it beat a diy sit3, pass labs xa25, atma-sphere m60s, a lyngdorf tdai-3400, and Coincident Frankenstein 300b monos.

In regard to this discussion, it has an output impedance of .2 and a damping factor of 40.

And @khragon, I suspect you’ll still love the speakers with your current amps, even if they’re not the ultimate match. If you happen to be in Colorado, I'd happily bring over the f4 & sit3 for a comparison.

cal,
I suspect that the F4s would quite likely work out well with the Nenuphar. I'm somewhat surprised you preferred them over the Atma-sphere M60s and the Pass Labs XA 25 with your speakers.  I get that the Frankenstein's 8 watts isn't enough for your PRE. The Frankenstein would very likely be an excellent match with the Nenuphar. 
Charles 

Me too Charles, me too. I would never have believed it if I hadn’t heard it with my own ears. I blame it on the transparency of the f4 paired with a second harmonic distortion character (w almost no 3rd and vanishing amounts of higher order harmonics)...

And, totally agree that the Franks should be just spectacular on the cube audio drivers. Wish I could have afforded to store mine for just such an occasion. As you know, I absolutely adored my pair...

(Incidentally, I just bought some .9999 solid core silver speaker cables based on an old comment of yours that had been rattling around in my head... Just as you said, putting in silver added beautiful, natural refinement to the system with no drawbacks over my previous duelund tinned copper. So happy I remembered reading the suggestion from years ago. I already had Occelia silver interconnects based on your recommendations, but am planning to rewire my amp, pre, and speakers to take it all the way through.)

@cal3713 Thanks for the offer, unfortunately I’m in S. CA.
I am confident that my current amp will sound wonderful with the Nenuphar... may not be match made in heaven, but at probably heaven on earth none the less.

From Cube Audio website, there’s mention that most solid state amp will match well, so I’m going to go with that for now until I can listen for myself:

" The Nenuphars are dedicated for rooms of 20 - 40 square meters (my living room is 30 sq meters). They are a perfect match for a tube amp with at least 3 Watts per channel. Our personal preference is somewhere around 2A3, Px4, 45 tube-based amps. Nonetheless, most solid-state amps (especially those working in A-class) are also an amazing match for the Nenuphars. When it comes to placement, they can be placed both forward and placed right against the back wall. They like about 5-10 degrees of toe-in. "