???Anyone Here UpGrade From Yaqin/Cayin/etc... To Another Tube Amp Considered Hi End???

I agree that the topology and the sucess of its implementation and quality of parts determine the ultimate sound quality level  of the amplifier. Pure class A single ended (Very simple circuit) KT 150 with high quality output transformers should sound fantastic.
Charles

Farther down the yellow brick road Dorothy.
Today I found the nerve center worthy of my amp/speakers & headphones(HiFiMan Sundara & Audeze LCD3)...From the side of the industry I believe is the finest driving force behind DAC technology today I went to the desktop audio industry & Burson Audio of Melbourne,Au...
 If you aren't familiar lets just say Burson gives you $5000.00+ worth of performance in a compact,superbly technical,fabulously spec'd & meticulously constructed piece of equipment,sold direct for $1000.00+!!!
 I'm going to chew my nails to the quick waiting on everything to land in my living room,I've waited 45 years for a system like this...

@freediver  I've had four or five Burson products over the years (160 D, Soloist, Virtuoso, Conductor V2+, and one more I think). They all drove my Audeze LCD 2.2, X, HD 800, Hifiman 400i and now Arya VERY well.  The DACs inside are pretty nice; far from the last word... But nice. The Preamp section of my V2+ was amazing. I took it over my buddy's place who has a passive with Audio Consulting wire and it held its own.

Not trying to be a you-know-what but I loved the headphone output of my Hegel driving my Arya so much, I sold the Burson. 

Enjoy!

Oh, and built like a tank. 

I went from Consonance EL34 70 watt PP A/B monoblocks to Art Audio EI KT90 50 watt stereo Class A PP. The difference was a more refined, detailed sound probably due to higher quality output transformers. The Consonance output transformers are noisy. Output transformers are one of the most important things in a tube amplifier design.