I find the difference quite hard to hear on albums, but you can be sure that the vast majority of albums you hear are recorded on either tube amps, or direct through Pods and such...although almost exclusively tube amps...
There are a few exceptions to the rule tho...for instance, Dimebag Darrel played through Solid state Randall amps for most of Panteras life span...not sure if he used them in studio though...he later switched to Krank Krankenstein tube heads for Damage Plan, although again, I am not sure what he used in Studio.
As for Chilli Peppers, John Frusciante is famed for a large collection of vintage Fender and Gretsch guitars...I think he would probably record most of his clean stuff on vintage Fender amps (judging by the sounds) and his (not all of, obvioulsy he has some times when real high gain stuff is used) dirty sounds on not-so-high gain amps, maybe a marshall 1959slp or summin...dont know why I'm saying all this, because it is all guess work, but I'm enjoying the guessing...
how accurate do you guys think I am? what amps would you say Frusciante uses?
the difference between tube amps and solid state amps is that tube amps use vacuum tube technology, this is largely considered obsolete in most industries except amplifiers...it is old technology.
Solid state amps use much more practical and cheap "transistor" technology...
as for sounds...Tubes have a much warmer, natural sound...although to be perfectly honest most people (even most guitarists) could probably not tell the difference between a solid state and tube amp if they were blind-folded and played both amps.
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