There are a few threads on this. As Raul points out it is very difficult to get very low noise in an all tube phono stage.
Difficult but not impossible. To get low noise with tubes you do some of the same things that are done in solid state preamp- particularly those that have opamps:
1) have a tightly regulated power supply2) use differential inputs3) use effective constant current sources for those differential circuits
In addition you simply parallel tube sections as part of your means of reducing noise.
The reason differential gain stages are used in solid state (and in some tube phono sections) is that for every stage of gain that is differential, theoretically you get 6dB less noise. This adds up- if you have two stages of differential gain, that's 12dB lower noise. But to that theoretical limit the constant current source really has to work.
If you do this then its no worries getting a phono stage to work fine with a cartridge of 0.2mV with gain to spare.