So i have my Marshall Hybrid(AVT20),will it make any difference if i change the pre-amp tube in in,and if it would make difference im looking for a thicker,warmer,cleaner tone,and i dont have money for a speaker for it,because my guitar need new pickups(these ones http://accessories.musiciansfriend.com/product/Seymour-Duncan-Hot-Rodded-Humbucker-Set-?sku=300030 ) because the stock are CRAP even through my friends all Tube Vox.
SO what Pre-amp Tube if it will make a difference!?
Ibanez sz720fm,Ibbly RG350DX, Custom Tele-> Dunlop 535Q->RAT Pro co II-> Ibanez Fuzz->Marshall Haze 40.
Tascam US-800 and a hand full of Mics into Nedundo 4

my music, new recording on the way in 2014

[B]insert witty italicized quote here
I heard of a guy who has a VOX hybrid.

He said he changed the original tube for a NOS one from a Mesa Boogie, and claimed that the sound became much better.
Purple string dampener scrunchy.