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

Hi sale84,
Your situation is totally expected and predictable.
The designer/builder has clearly stated the Cube Audio Nenuphar is specifically meant to be used with amplifiers possessing
1 little or no NFB
2 Relatively high output impedance
3 low damping factor (DF)

The special single driver has a very powerful magnet/motor assembly and is very well damped and controlled. An amplifier that utilizes high levels of NFB which results in very low output impedance and high damping factor is exactly what you need to avoid.

It is no surprise the superb Nenuphar speaker sounds magnificent with a high quality SET amplifier (Most often zero NFB) such as your Line Magnetic 845 or David_ten’s teriffic 2A3 SET mono blocks. High NFB amplifiers (which yields very low output impedance) are detrimental. IMO the Nenuphar is worth every penny based on feedback I’ve received. BTW solid state amplification are  fine as long as they adhere to the designer’s recommendation/ guidelines.
Charles

Saleh84,
Your Gryphon is an excellent amplifier "with the right speaker". Some speakers demand amplifiers with high current delivery with lower output impedance due to low and difficult to drive load characteristics and often steep phase angles. The Nenuphar is the antithesis of this type of speaker. Your LM 845 wouldn’t be a good choice with these current hungry speakers. I much prefer your LM /Nenuphar approach.
Charles

I agree, the gryphon diablo is a great amplifier. And i believe the bigger gryphons are some of the best amps - the house sound of gryphon is excellent. However I think it was my choice of speaker being the KEF ref 5s which was the wrong move, they need a softer presentation amplifier probably, and in all honesty as much as i tried to make that combo work, it still did not sound right, certainly not a musical/emotion inducing sound but rather mechanical. It had a district colouration as well. If I had a B&W 802 D3 for example, probably I would have been ok with the diablo and kept things as is.
I could have travelled that route, but hearing the nenuphar's over and over again at my friend's, i couldn't resist anymore, also i was craving to get back to tubes - i started with a tube headphone amplifier, changed to SS only when i moved to speakers camp. The nenuphar was made for tubes, so all was good!

The next step for me is getting a pair of the newly announced cube audio sub 12. I always wanted to experience stereo subwoofers, even with the KEF. I was about to buy a pair of REL S/812, then came to know about the cube offering. I opted for it hoping for a better integration, hope that i made the right choice. Will keep you guys posted how it goes! 

“... Is it just me or is 15000 clams for a single driver speaker seem somewhat pricey?...”

May be yes or may be no...

https://www.dagogo.com/feastrex-makoto-loudspeaker-system-review/

Dawid Grzyb // HiFi Knights addresses this head-on in his review:

http://hifiknights.com/reviews/speakers/cube-audio-nenuphar/

The Cube Audio Nenuphar speakers list for USD $14,900 shipped via Refined Audio, Forest Park, IL (Chicago). Jon Ver Halen is the proprietor.