2 vs 8 tubes in preamp, sound difference?

Just for a different perspective...designs that are using 8 preamp tubes most likely are the more expensive preamps but no idea if that relates directly to sound quality. There are some good tube preamps with just two tubes. 

So, tell me, how does one learn soo much about audiophiledom.

Putting together and upgrading many systems really helps. As does visiting very high-end dealers with great sound.