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

I've got about 35 hours on my new Nenuphars, swapping between First Watt SIT-3 and LTA Ultralinear amps.  The break-in changes to SQ have been subtle and what you would expect--increase in depth, smoother highs, tighter bass.  But the difference between the two amps is not subtle.  SIT-3 is more mid-range and mid-bass oriented, slightly darker, earthier.  A tunefully dense, very engaging sound.  The Ultralinear is like switching to a brighter bulb, recording space more visible, more air and dimension to instruments and voices, better dynamics.  I find this openness to be even more seductive than the SIT-3, delivering a heightened sense of you-are-there.  Bass is very similar, tuneful, tight and deep with both--interesting since the two amps have very different damping factors (LTA being about 1/5th of the SIT-3).  Maybe the distinction in bass will become greater once the speakers have had a chance to break in more.  If I had to make the choice right now--more a matter of taste because they both are a great match--I would pick the LTA.  To me it just offers more of the magic these speakers make.  Which begs the question: "Would a 2A3 or 300b amp often even more?"  I've put the word out locally for a loaner...but that's just audiophilia curiosity talking.  I'm a totally enthralled camper with the Ultralinear.

i have been following this thread because of my love for single driver speakers but mostly just envy. with that said, i tried a handful of amps with my omega loudspeakers and the most satisfying pairing I've found is with LTA. i certainly not have reached into the stratosphere $$$ of SET amps, so i can't can't speak to those, but the LTA is simply magical as noted above. 

Stephen, thanks for keeping us informed. I have not had the opportunity of trying the LTA. Out of the solid state amps I can recommend the Bakoon 13R integrated amp with Cube Audio speakers. Grandinote and Trilogy may also be worth auditioning.

@jmolsberg If you're willing to DIY, the entry price isn't as bad as it seems.  Jon @ refined audio was recommending a simple 1 cubic foot sealed box with the 8" driver if you're going to augment with a sub system.  Cube audio has a lower model featuring the same basic technology (the Fc8 Driver) for $1500/pair.  The new 8" neo drivers from their top end models go for $4700/pair.  Still expensive, but reachable for more people...

And @stephendunn  Wow, congrats.  Sounds like the most positive early impressions you could possibly expect.  Great to hear, and makes me even more interested in trying out these drivers.