I have to respectfully disagree with many here. In my humble opinion, It really doesn't matter whether the pre-amp or amp is tubed or solid state. it matters what the listener likes to hear.
As I have written time and again, there are so absolutely wonderful tubed equipment. However, there are also some absolutely wonderful solid state equipment. Speaker-amp interactions aside for a moment (which is hard to do), a good design is a good design. A good engineer is a good engineer. Unless one purchases a price is no object piece of equipment, each manufacturer has to compromise somewhere.
My point, is don't drink the coolade. some people have preferences, and after demoing many pieces, they come up with their preference, that is fine. But, my advice is to set a price point (said this time and again) for a piece of equipment and go find both tube and solid state equipment that the manufacturer says will mate well with your existing equipment and hear for yourself.
I have heard some outstanding tubed pre-amps and amps. Same for solid state. But to say that tube is better than solid state of visa versa is just simply.....wrong.
Audio Research tubed electronics are wonderful and I own some. Great stuff. I also own Mark Levinson equipment. I've heard Boulder equipment. Very nice (ridiculously overpriced in my opinion). I haven't hear like priced Pass equipment of Gryphon, etc.
So for a person to say that one is better than the other, implies that he/she has hear every piece within that price range and that simply isn't true at all.
Don't get me wrong please. And please, do not attack me. I like my Audio Research REF 3 pre amp in front of my Mark Levinson 23.5 amps. And yes, the 23.5 amp is still one of the best amps out there for the price. But, I was finally, after two years convinced to purchase the Audio Research REF 250 amps, because they simply were wonderful. They couldn't complete with the Mark Levinson on the low end, so my bass drivers on my Martin Logan Monolith III speakers still use the 23.5.
And if I can afford either a REF 5SE or REF6 pre-amp, I would grab it. Audio Research makes really good equipment.
But, lets be truthful and real hear. Tube is better than solid state? I don't think so. Nor do I believe that Solid state is better than tube.
Pick a price point, grab some tubed and solid state equipment and hear for your self.
You may decide that a tube pre-amp out performs the solid state pre you compared. Then, you will know the answer.
You may also find out that the tubed amp in your price range just doesn't do it with your speakers. Oh well.
This is where the fun starts. It is okay to take someone's advice with regards to auditioning equipment, but please do not buy the theory that one design/configuration is better than the other.
it just ain't so.
enjoy