Lavardin IT or Jadis DA50 Signature?

Difficult but hesitating between a Lavardin IT amp (SS) and a Jadis DA 50 Signature (tube). Who can advise me wisely?
Speakers: will change into Dynaudio, Apertura, Triangle, Totem,..
With these amps, I would suggest you decide what speakers you will have first. This will avoid making a mistake as these two amps will not like the same speakers.

Speaker selection should be heavily influenced by the room dimensions and materials. Amp selection will then be heavily influenced by the speakers.

arthur is correct. if it turns out to be a toss up, go with the legend...jadis
Take the Lavardin and get your hands on a pair of Living Voice OBX ,a combo loved by many.
I have just changed my IT and use a tube amp too, Viva Solista not Jadis. I have heard Jadis on a number of occasions. The IT is everything people say of it, but only 50 watts. It is fast clean, transparent, but it lacks drive. It is on the polite side of neutral. It worked well on my Living Voice Avatars, but was running out of puff on my new Acoustic Zen Adagios(89db, ok, but only just. As a matter of interest, my Karan K180 has many of the IT virtues, but certainly more base control and better dynamics. A clear step up with the Adagios
Ok, if you want me to pick both speaker and amp, then here goes. I am assuming your room is 16-22 m2 and neutral.

For the speakers, I would go with Apertura Thema. Their tonal color is the most detailed I have ever heard and they have microdynamics like crazy. But when you want loud sound, they do that too and keep it all together like a champ. Very impressive speakers that are also surprisingly efficient. How I wish I could bring a pair back from France....

With these speakers, I would keep the common voice and get the Jadis DA30. I say the DA30 over the DA50 because it has undergone a number of changes since the 50 and it also has "pre-outs" and "amp-in" in case experimenting down the road is of interest to you. And it has nearly the same power. It also can handle many more power tube types than the 50 thanks to its wide-range auto bias which would allow further tailoring to your personal tastes - it will save you from having to try piles of different cables to get the same result.

I own a Jadis DA50 signature, it is the best amp/preamp setup I have had for my Avantgardes UNOs, and I have tried and owned at least a dozen amps. Jadis sound is lush, fleshed-out, organic and very musical. You wont feel the need to chenge it in a long time, and since it is a Pure Class A design, almost any over 90dB spkr will make it.

Hope this helps you out.

The IT would easily be my choice.

I don't understand the power/efficency issues with the IT (or the IS) that people seem to be experiencing ? I've heard an IT easily drive a pair of Totem Model One's (hardly the last word in efficency) in a medium size room to an adequate level.

I think people these days are becoming power hungry at the expense of fidelity.