That doesn’t even make logical sense.
Read again sunshine, maximum master volume with minimum "tube gain" for loudest listening level. Will give lowest noise figures
I forgot to mention that when you purchase an Axiom passive preamp the mfg will ask you what power amp you will be driving so that it can be configured to deliver the best sound.That would be say a 100kohm passive for amps like many Rogue Tube amps which are 1mohm input impedance.
Or at the other end maybe a 5kohm passive for amps with 20kohm input impedance. And then some in between these.

