I have not read all the posts in this Thread and after approx' 30 Years of use Tube Amplification no longer use a Traditional Design Tube Pre-Amp.
Valves that are mentioned in other Posts, I have got a familiarity with and have even Rolled types as Vintage thought to modern versions.
I have been demonstrated Tube Pre-Amp's that are carrying a substantial retail cost, 'for my budget anyhow'.
A complete turnaround occurred when I heard a Basic Pass Nutube Korg B1 Pre-Amp as a Basic Model.
The impression made was quite something, not too further on, I was demonstrated a re-think on this design, where upgrades were produced.
The upgrade Version Blew me away, and a few others who were at the Debut Demonstration.
I have now been loaned a Korg B1 for a considerable period, which had minor tweaks to the circuit over the standard design.
Within my system this has been A/B compared to Pre-Amps owned and loaned. It has stood out as a very worthy device.
I have also had the earlier mentioned Upgrade Version compared to the loaned Korg B1, and the Upgrade has been superb.
This Pre- Amp has made a big impact on the Local HiFi Group and there are now Five Versions in use excluding a Balanced Version produced.
At present I am having a Balanced Version produced for myself, that will incorporate all the circuit upgrades that has been extremely impressive to experience.
This is not an expensive option, there is lots of support to be found, but might need a support from a EE, as I have chose to.