2 vs 8 tubes in preamp, sound difference?

You only need enough. Having more tubes is no better than having more woofers.....in the right configuration and application, it could have some benefit.... but could also just be more, and maybe too many..

Absolutely not! The fewer the tubes the better. The finest sounding amps are SET with one output tube per side. That goes double or preamps. 

sure -- exactly 4 times better!!! go for it!!!

just like salt on food

ibuprofen for pain

ambien for sleep

more more more... yep, that is the answer...

@emergingsoul Did the OP simply mean # of tubes or # of active elements? Just because an ARC SP9 has 2 tubes does not mean that it does not have any other active components. Then the argument is tubes vs solid state and not the number of tubes.

Seems 2 tubes is very close to ss.  What is a hybrid preamp?

have heard a higher priced ss is just as good as tubes and handles higher and lower end freq better than tubes