I think the most important question is this,do you listen or leave your system on for extended periods of time?If you do,I wouldn't recommend tubed equipment,especially if you use your system for movies and/or television.I have music playing almost continuously when I'm at home.I ended up getting two different systems, a solid state for most of my listening and a tubed for more critical listening.If,on the other hand,you only listen for a few hours at a time,I would highly recommend a tubed system.Start out with a simple integrated and see how you like it.Learn the basic maintentance and upkeep and you should be fine.After some time,research and experience,step up to a level you are comfortable with.You can make this is simple or as difficult as you want,same as any equipment.I can't answer your specific questions because there are too many variables involved.Maybe someone else will stick their neck out on that!!!I hope this basic rant somehow helps you.Good luck.
Tube pre-amps/line stages are as simple, or as complex, as you fear/require depending on your actual usage and sonic demands.
For example, I'm aware of a tube line stage which can be left on 24/365, uses easily acquired and inexpensive small tubes which have a manufacturers claim of a 5 year life expectancy. It is as close to plug and play as you can get and (if you like it!) sounds pretty good. If you WANT to change the tone you can by putting in a few different tubes BUT you don't have to. No frills, not eye candy, will not impress anyone! Not built like a tank either. But then its simple and there is not much in it to fail either. Used it costs less than $1000. For me it is a bargain in that unlike solid state stuff I at least have an option to change its tone to accommodate a new piece of equipment (recall the importance of synergy) without having to start a search for a new pre-amp.
I also have a fairly decent high(er) end pre-amp with a phono stage. Another no frills unit, 4 tubes, sounds pretty good with new production tubes, well built, and looks nice as well. Cost well less than 1000 used.
Whether you become paranoid about tube selection or not depends on how anal you are about things, and or how much you feel you want to or must depend on others for advise to get you where you want to go. I've been fiddling with tubes a long time now and unhesitatingly use new production tubes often, and often in preference to some of the NOS tubes you see others recommend. So I guess you can take 'tubes' as far as you want to go, or not, but with SS stuff you are fairly stuck with what you get, tonally speaking at least.
We know ourselves better than others so do what makes you comfortable. FWIW it took me a long time to jump from SS stuff to tubes for reasons of fear born out of ignorance but I've never looked back. And I used my first tubed CDP and first tubed pre-amp for many years without ever exploring tube rolling or maintenance.
IMO you need a dealer (you can work with) that can support tubes. IF you have one, then you are basically home free. Otherwise, stick with the big names that do a good factory job. Audio Research is the premire company in that respect that I know of. Around forever, and work on anything they ever made.
Other companies do too, but AR is the one I know and would trust 100%
(I have one AR product a SP-15
I don't think you need to really panic about making a move into tubes;I was a solid state guy as well then moved into tubes using some of the advice already mentioned;I also bought a used tube tester and it did not break the bank as well.Tube rolling is not that hard as you can always ask for advice in these columns as you did and you will get very solid advice from the members and manufactures who respond to questions as well.
Price wise you will encounter the full gambit of $$$ and you will need to do some research if you want to take the dive.Leaving tubed equipment on or off I think is a personal choice as you will hear people who leave on 24/7 and ones who power off;I have a standby position on my gear and lets me keep it powered up,this is a option that may want to consider as well.
Do you have any gear already in mind?Tell us about your room,what you like to listen to, and what sound are you looking for moving into tubes.
moving to a tube pre for under 2 grand should be a very satisfying move; in my case, doing so was the best upgrade so far in terms of enjoying the music far more than my already very good ss processor. i also bought new electro-harmonix tubes and tube dampers that made another significant improvement in musical enjoyment. in my experience, the results far outweigh any initial misgivings about tubes; they simply sound glorious!
Udo - Youre complicating things way too much. For example, I bought a used tube preamp (Tube Technology Seer) a couple of years ago. Ive never replaced the pair of 12ax7s it has in it. Even if I needed to, its pretty simple and straight forward. 12ax7s are a very available/common tube and can be had for cheap to very expensive.
Im sure that my Tube Technology Seer tube preamp is one of many products out there that are simple and straight forward and allow a person to enjoy tubes without a lot of headaches, maintenance, or tweaking.
To your last point Whether or not it would really be a satisfying change, only your ears can determine that, dont solely rely on what others have said or experienced in their systems.
I second Elizabeth's post. I have an ARC SP-16, which has six tubes. Before I bought this pre-amp, I had the same concerns as Udo. But Audio Research makes it a no-brainer. I've had the SP-16 for 5 years now, and have just reached the end of the tube life. (I use my pre-amp for music and movies, but I turn it off when not in use.) I recently ordered replacement tubes from ARC, and although you pay a premium by ordering the replacement tubes from them, you have some assurance that you are getting quality as they test all their tubes prior to shipping. Replacement tubes were labeled "SP-16." How easy is that? The next pre-amp in their line (the SP-17) only has two tubes, which makes things even simpler.
Tube managment and worry is simply much less of a concern than dealing with them in an amp (that too can be managed). The only issue you do need to be sure of is that the output impedance is a good match with the input impedance of your SS amp. You want the ratio of amp to pre impedances to be at least 10 to 1, but the bigger the ratio the better. So if you have a tube pre with a 1,500ohm out put impedance you want at least 15kohm input impedance (must tube amps have 100kohm so it is almost never an issue).
There are tube pre-amps better than solid state and solid state better than tube. It really isn't a question of tube sound vs. solid state either because each product sounds decidedly different than another, solid state or tube notwithstanding. It depends on how that product sounds combined in your system and if you like the sound. Tubes begin to lose life the moment you apply electricity to them. Same with solid state. People just for some reason think differently about solid state life than tubes. that is wrong. First, tubes and solid state's bias have to be adjusted after so long. Second, solid state do lose life and need replacement also. No one talks about that because it is much more difficult (not impossible) to replace transistors than tubes. I do it all the time. There are much better sounding and more linear transistors today than yesterday and if you find transistors that have the same voltage, current, hfe, etc. characteristics and replace the old ones, you will find an absolutely wonderful sounding amp. Unless you get into the tube of the month club as I have seen, then you should stick to the recommended tubes from the manufacturer. That is simple. Either they are matched sets or not. Either way, go by what the manufacturer recommends for replacement. There are several places to buy tubes. Some places test, burn in and measure tubes and match them for your amp, pre-amp before sending them to you. Other's, well, you are on your own. I like the Audio Research REF 3, because it just sounds wonderful in my system. I also liked the AR SP 11, and the Robertson solid state pre-amp was better than the AR SP 9 MK II believe it or not. But, the Boulder top of the line, blew all of them away and it was solid state. I'm sure the Mark Levinson and Pass pre-amps along with YBA and many others also stack up very well with Tubes. It depends on how they sound in your system and whether it makes you smile when you listen. If you find yourself sitting for hours without fatique or the desire to get up. then you are there, tube or solid state. find what works and sound good and right to you. Don't go by what other's tell you. Borrow equipment and listen at home. Also, don't trust other's ears, their hearing may be faulty and they don't know it. Happens all the time.
Borrow equipment and listen. Tube or solid state. But remember, compare within the same price range equipment. they are designed based on price range most of the time. So, compare apples to apples. don't compare a REF 3 to a $200 solid state pre-amp and say the solid state pre-amp sucks. It comes down to what you like in the way of sound from your equipment in your house and most importantly, your price range.
But, difficulty with tubes? They really are simple, not very complicated.
Listen and enjoy.
Just for some real world experience here - in my 'second system' which is composed of mostly vintage pieces - I run a refurbished Dynaco PAS-3X. The line section tubes, a pair of 12AX7s, are original Telefunkens. For the past two years, the PAS gets anywhere from 5 to 12 hours of use a day. No problems with tube life, even with the Shuguangs I put in the phono section.
Of course some tube preamplifiers will "eat" tubes faster than others - it's design dependent - but small signal tubes usually last a very very long time.