the best 'tubey amp - warm,smooth,liquid' ?

Zabiaud..If you are after that warm, lush, very smooth sweet sound then you should consider the tubes rather then the brand of the tube amp itself. There's a company out of China, called Psvane & Shuguang. Their tubes are made like tubes were in the late fifties and early sixties. With heavy filaments and thick envelopes. They are pricey but have a very long life. The tubes are beautifully cased in wood boxes. They are the best built tubes on the market.
Go to the Grant Fidelity website in Canada. They are the North America Distributor and you can buy direct. Again, these tubes have a very classic sound that was common fifty
years ago and are warmer and richer than other tubes of today. Some may find these tubes too warm and laid back and overly lush. but thats what I prefer personally so it all depends how much warmth your after.

I'd say it's more like EL84 based amps.

I wouldn't go with an off branded component. If you need that soft sound go for a Mac.

"actually i have a difficulty to match speaker systems with."

What's the difficulty? What speakers? What preamplifier? What source? Budget?

Amplifier suggestions without any system information, clever.

The speaker you have will dictate what is suitable for you in terms of an amplifier. Is your speaker tube friendly? What is the impedance curve like for your speakers? Are they sensitive enough to be driven by tube amps?

Synergy of the system is very important. Not knowing the details of your system it is very difficult to give sane advise.

If I was in the market to buy a tube amp, with no nonsense engineering, sensible pricing and superb sound I would have Cayin at the top of my list. They make a variety of amps to suit every budget and power needs.

Hope this helps