Went to a Guitar Masterclass at PMT last night

[SLUDGE FACTORY]

Tasty playing! I normally run my Les Paul straight into a cranked Marshall type amp, and the Telecaster into a Fender/Vox type amp, either clean or on the edge of breakup.

FX is for used for variation, or when you are trying to get a specific sound. The FX pedals are usually run into a clean amp.

For something like this you definitely need FX pedals ..

When he was in KYUSS , he plugged his Les Paul straight into a bass amp for that dirty sound

[Wales-Bales]

When he was in KYUSS , he plugged his Les Paul straight into a bass amp for that dirty sound

Not sure about Kyuss, but for QOTSA the bass amp is part of it, but his main trick is using a Maestro Parametric Filter MPF-1 that was designed by Bob Moog back in the 1970's, which he has since been replaced by a Stone Deaf PDF-1 pedal (which is an enhanced copy of the MPF-1).