Playing at low volumes, will changing the preamp tubes make more of a difference as opposed to changing powertubes? There's no hiss or crackling or microphonic issues, I'd just like to get a more smooth gain out of my Peavey Classic 50 (hence the reason for my question in another thread about combining a 6505+ head with it). At louder volumes the gain sounds quite nice but at lower, normal-sized rooms, would it make a difference putting new preamp tubes in. The current JJ 12AX7 preamp tubes have been in there for a good 2.5 years and have seen a fair amount of use (at max gain). If the power tubes were replaced, how much of a difference does the Groove Tube power ratings make on their EL84? ie: 4 vs 7? That's what I can get locally.