Maybe there was something wrong with these nCores?
Desalvo55,
The Ncores sound best plugged directly into the wall. I'm not sure of your set up, but that is the way that most users found them to sound best. There are many threads about the Ncore over on the Audio Circle forum. Perhaps there may have been a deviation in this particular build? Dunno?
Your Joule Electra amps are a superior sounding tube amp, no doubt about it. They offer a true 3D bloom that can be found in only the best of tube amplification. The Ncore is SS Class D, and as DIY can be put together for about 15% of the JE VZN 100's. Your high sensitivity speakers are pretty much a non issue for the Ncores. Many are using them with high sensitivity with great results.
Hey lets face it, you already have a fantastic sounding amp and the Ncore didn't float your boat. No biggie!
Beauty is in the ear of the listener :-).
Enjoy