I use tubes in every component in my system except the amps driving my subwoofers. My favorite smalll input tubes are detailed in the Doge page.
Recently I’ve acquired a set of Shuagang Kt88z Treasury series. These are beautiful sounding tubes, open, transparent with a warm but open midrange and without a hint of glare in the upper mids and treble. A big improvement over any Russian kt88 or Valve Art or other standard Shuagang tube.
Ignore what a lot of people are saying on forums about new old stock and about Chinese tubes most of these guys have not even listened to the tubes they are condemning
Lately I’ve added a pair of Gold Lion Genalex 12au7 to my power amps and I am very impressed.