Maybe tube preamp

I would have to concur that Aric Audio would be a good place to start. I have several pieces from his bench due in large part to the sound floor. If it's not dead black silent, it doesn't get out of his shop. That holds true for both amps and preamps. Plus, as has been mentioned, he is refreshingly genuine to work with and is as passionate about tubes as anyone I've met.

MarkAinsworth: I have only seen photos of the 6SN7 Line Stage, but that was enough to foster a "few" conversations with Aric about it. After learning about the inclusion of some impressive components like True Copper caps and the 5u4 Rectifier, which should add to the tone and body of the sound, I liked it even more. My Enigmatic Mono Blocks run 6SN7s, chosen over 12AX7s during design due to the larger and more dynamic sound of the octal over the 9 pin mini. I am also a fan of the 5u4 Rectifier (black plate) and already run them in both my Special SE and in my Unlimited. All these things together, make the $400 less significant. I do not stop being impressed with how the Enigmatics sound, and soon they'll have a 6SN7 Line Stage in front of them.

Wolf_Garcia: I run both 6SN7s and 6SL7s -- the 6SN7s are in my mono blocks and the 6SL7s are in my preamp. This decision was made to take advantage of the fact that the 6SL7s bring a little more gain than the SNs, which I wanted. With respect to the "Red Base" -- I believe that it is, in fact, important. I have rolled a lot of both the SNs and the SLs in order to be able to say that. New production, NOS/NIB, it doesn’t matter, nothing sounds like a red base 5691 which was RCA’s Premium version of the 6SL7 or a red base 5692 same for the 6SN7. Premium because both included extra support rods between the top and bottom mica spacers making the structure more rigid, and in doing so, eliminating microphonics; and long life cathodes rated by RCA at 10,000 hours.
                                                                                                                           RCA also made both in a Black base as well and I must say I find it very difficult to tell them apart. The Black base seems to be easier to find and they command less money.

Thanks Wolf, just to be clear, it's "Black Base" rather than "Black Plates."