Questions about Preamp Tubes

Thanks for all the responses guys - you've answered all of my current primary concerns. However, I encourage you guys to continue your discussions at the tail end of this thread as I'm somewhat new to this audio hobby and am learning all the time. I'm enjoying reading what you guys have to say.

As far as specific equipment I am considering Thorman, I'm not entirely sure if I plan to buy a preamp in the very, very near future and am in a more factfinding type of stage, so I will leave that for a more pertinent time.

The issue of greatest concern with regard to the small signal tubes is not replacement but noise.
I also want to warn you that tube "rolling" is a very addictive hobby that could end up with you begging money from relatives for more NOS tubes.
I don't know in truth about longevity, I have had no new tube failures with the exception of power tubes. Some of the tubes I have were used for 7-8 years and are still fine. Others I run for a few months and they have become irritatingly noisy and a real bummer. If you shell outbig bucks for a special old stock tube and find it useless after a few months you are Sh** out of luck.
I wouldn't forgo a tubed preamp for a SS in a line stage simply because I like tubes. However I don't think of any tube being perfectly noise free when amplified in a phonostage. The order of amplification is so great it is nearly impossible to maintain a truly silent tube phono stage. Others will argue, you will see.
In any event Tube power amps or integrateds produce a bigger, more obvious, holographic three D sound stage, than any SS gear at any price, that I have encountered. Since I go to audio shows and am a member of a large audio group I have heard top flight SS gear. It sounds great but nothing like a tube amp.
In the end I think my AE-3 tube pre is a miricle for 300 bucks.
I happen to own a legendary preamp, which is one of those you mention, an ARC. An SP6B specifically, which is a generally admired and sought after pre given that it is 25 years old.
I prefer my little 2 tube AE-3 which uses 6SN7s. I happen to really like them but I haven't the resources to buy a SLP-05 for 7-8 thousand.
My two cents in summary worry about your power amplification!
If you use power tubes you will hear the tube magic. Don't fall for the tube pre is all you need bit. It is not true period.
If you want to use an SS preamp you will still hear the magic. The other way round is widely believed to be the case, ingnore the insane, hopeless, clones.
A tube in a preamp or preamp section of an integrated accomplishes nothing without using power tubes.
Good luck and believe me or just find out yourself it took me only 6 years of experimenting with tube preamps to hear Nirvana when I finally bought tube power amps.

Mechans,

Your points ring true. I'd agree you can get more inherent "tubiness" from a power amp than a pre amp since the signal transformation that occurs in the power amp is of much greater magnitude than that which occurs in the pre-amp.

But I think I would assert based on my experience that a pre-amp can provide a significantly more tube like sound if designed to do so as well. I've confirmed this on many occasions with my Carver c-6 pre-amp.

The c-6 is actually a solid state pre-amp that provides two sets of pre-amp outputs, one voiced like solid state and one voiced like tubes.

And yes, the tube output voicing does work quite well. It sounds very much like the better tube gear I've heard. The ss outputs do not. I'd wager that any set of ears familiar with the general difference in sound between ss and tubes could easily identify which is which.

The tube voicing provides a sound very much like what Newbee describes above. The solid state voicing in comparison sounds very much like what Newbee describes there as well in comparison.

So if a ss pre-amp is able to provide a more "tubey" sound, I have no doubt the real thing can as well.

The more I compare Carver's "mid-fi" stuff with other more blue blood designs that tend to garner more respect in the audiophile world over time, the more respect I have for what he was able to accomplish in terms of delivering good sound at modest cost.

How did he make a ss pre-amp sound like tubes? I suspect it has to do with the manner in which the gain is applied to the signal. With the ss voicing, dynamic range is clearly greater at the expense of microdynamics. With the tube voicing, the reverse is the case. In many a/b tests I've done with these two alternately voiced ss outputs over the years, the difference is clear as night and day.

This also leads me to believe that other ss designs can achieve a more "tubey" sound in a similar manner when designed to do so, without the the extra maintenance issues associated with real tubes.

I've heard a more tube like sound I think in ss systems from Musical Fidelity, Krell, and Classe, for example.

So in my case, I do like the tube sound and looks as well, but I'm not quite sure that the extra cost and headaches associated with real tubes are absolutely required to achieve the desired sonic results.

I also believe that while ss can be voiced for modest cost to sound like tubes, I'm not sure the reverse is true. The tube gear I've heard capable of resolving (this is different than microdynamics) competitively with good ss without losing the inherent "tubiness" of the sound have all been quite expensive.

I agree with the comments that tubey sound could be obtained by only tube power amps.
SS preamps give cleaner (less thd )sound but tube pres give more opennes and palpability (basic tube characteristic)