What is your favorite tube for a preamplifier ?

Personally I like what the classic 6SN7 vacuum tube does
for opening up the soundstage and the 3 dimentional images it produces,along with the 5AR4 rectifier tube.
Please add your opinions and why.
Hi 2 channel

I recently got a cyber 222 and am enjoying it very much. I also replaced the 5AR4 with a mullard and replaced the 6SN7 s with NOS tubes but not all the same. Each one different in fact as I read that a combination of them can sound good.
My pre was modified by parts conexion so is not stock. Was wondering how you changed the power cord ? Is that the one between the power supply and the pre ? Would like to hear your thoughts on the volume control too . I found there was not enough range between (4)and (5) so have tried some inline attenuators . They help but I think they have taken the highs away unfortunately. Be good to hear your thoughts.
The 7193 (2C22) is the king of preamp tubs in my opinion. I converted my Supratek preamp to use these instead of 6SN7s; much crisper and clearer treble, with images that hover in the room with you.
The 7193 (2C22) is the king of preamp tubes in my opinion. I converted my Supratek preamp to use these instead of 6SN7s; much crisper and clearer treble, with images that hover in the room with you.
I have used many the 6sn7 or 6sl7 are more bloomy not quite as accurate though the build of the preamp and coupling capacitors have a lot to say about the final sound also I use the 6h30 supertube in the special dD grade and I get plenty of soundstage quickness and musicality .I have the new Lector 0ohm preamp ,the beauty hear is that you have 4 choices on what kind of tubes you want to roll also please remember a good tube damper such as the Herbies he has several grades and a good power cord
and I strongly recommend using the better Silver fuses on all your gear your detail is clearly better if you gear is respectable.
6SN7s are nice as they have a low microphonic aspect. They are great in line stages and can handle a lot of current so wide bandwidth is easy. Although they have less gain than 6DJ8/6922s or 6H30s, the reduced microphonics compared to those tubes is profound- so it is easier to make a line section that is neutral with the 6SN7. Of course you can hand-pick the miniature tubes for low microphonics, but in doing the same for the 6SN7s the same advantage of the 6SN7 is realized.
Great suggestions so far.
If you are into DIY, 76 and 6J5 are two of the most linear tubes ever made.
The 6SN7 is a direct descendant of the 6J5.
Have fun!
Also agree with the 6SN7.

For me, so many 6922, 6H30, and 5687 based designs sound bright, glassy, and etched in the manner that many audiophiles often mistake for resolution or neutrality. I find many of them artificial and difficult to listen to for any length of time.
My Rogue Athena uses a quad of the 6h30 super tube and for good reason they are the most linear small tube made .
My preamp is very accurate and musical their smart parts
decision had a lot to do with that.
Hi Gang. In reference to Casouza's post stating the 6sn7 as a direct decendent of the 6sn7.

Although electrically equivalent and both employ the same octal base, the 6j5 is a single triode whereby the 6sn7 is a dual triode [basically two 6j5's in one tube] and are not direct substitutions.

While there are so many different flavours to experience in the 6sn7 family of dual triodes, and as mentioned by Ait in an earlier post.
In my experience, the 7193 is sonically superior to any 6sn7 regardless of manufacture... nos or otherwise.

Comparatively speaking: the 7193's sonic signature is a combination of the best of the 6sn7 family.

Combine the bass power and depth of the Kenrad black, the 3 dimentional midrange of the old tungsol round plate,the bloom of the Rca grey glass with the treble extention of the best nos sylvania's.

Although a little more difficult to find these days, they generally sell for a fraction of the cost of the nos 6sn7's.

the RCA12au7 NOS is my favorite tube.
Orpheus. Why is the RCA 12au7 your favorite? My Rogue Cronus takes a 12au7 and I'm currently using the Sylvania that came with the amp.
Ecclectique, you are correct, I forgot to mention that 6J5 has only one triode as opposed to two triodes in a 6SN7.

I wonder if you have found a military equivalent of the 6SL7, similar to your favorite 7193 in place of a 6SN7 ?
Best wishes for 2010
The NOS RCA 12au7 made a gigantic difference in my CJ PV10 and PV12. It is also less expensive than the other NOS tubes.
I used very expensive mullard NOS 6922's in my Audible Illusions M3A and got only a small improvement, but that could be because the M3A is so good that it is hard to improve.
Well, one of my favourite preamps (Atma-sphere) uses 6sn7s, but my other favourite tube preamp (Joule) uses 6350s which I never heard of - I think they were designed for TVs, not sure, but it sure does make for a nice sound preamp. My other tube preamps have used 6922s and/or 12AX7s. The old ARC SP6 used all 12ax7s I think, and for the time it was a might fine sounding preamp.
I think it depends on the build quality of the preamp more than the tubes. I have had a preamp that used only the 6SN7 family of tubes vs the other that used the 6922 family of tubes. The second pre with the 6922's sounded better because it was a better preamp. I never had a preamp, don't know if one is even available, that would accept both 6SN7 or 6922's which would be a better way to compare them, at least for that particular preamp. I see many posts from people that hate the 6H30 super tubes and others swear by them. It all boils down to the sound that is most pleasing to your ears!