I would say....
1- whats the diffrents between the Tube mics ,and the norlam once
For a good one?...about $3000...no really, a tube mic uses a tube(obviously), like a 12ax7(not all the time though) instead of solid state electronics to boost the signal enough to get it to the preamp without noise (or at least minimal). You would have to hear it to know the difference ( you will hear the words "warm" and "rich" a lot).
2- should i get a tube preamp with the tube mic ?
If you want. I do it all the time (but all my mic pres are tube so I really dont have too much of a choice). Theoretically, tubes and transistors should sound the same up untill the point of distortion, but that is subjective.But anyway,some cheaper tube gear isnt all its cracked up to be, so youll hear the word "noisy" to. I think youll probably get more mileage out of a GOOD tube preamp than a tube mic since a tube mic will have more "character" than a solid state.(like I said, youll have to hear it).Personally, I would use it with a good ss pre (if I had one).
3- for wich style its usualy used ?
Any style you want. Just as long as it sounds good.
4- should i get one for my studio ?
Sure, why not. Theyre a bit more picky that a ss mic. I usually let mine warm up for about an hour before I use it( I do that with my tube pres to) But,like I said , a good tube pre should be more flexable(really,a good pre amp of any kind in general would be more flexable) .
Depends on what its used for. I normaly use mine for vocalists that are too.....brittle? It can tame down some obvious frequencies that arent too appealing. But it can also bog down your sound if the singer or instrument is already....... full?...rich?... But,it can also be the perfect mic for a specific sound. Sometimes,with cheaper mics,if you use it on a large number of track on the same song, a build up of some frequencies can start to occur(but, this can happen with any mic).These are just very simple answers.
Anyway,the best way to get to know the difference is to hear it,instead of reading about it. Go to a music store and compare between a ss mic and a tube one. That would be the way to base a decision on. In all honesty, be prepared to shell out some cash, as real tube gear isnt what you would call cheap.