It squashes loud things down and then increases the gain of everything, which has the effect of levelling everything out and making quiet stuff louder.
You don’t need it if you’re using any kind of dirt, as increasing the gain then squashing (clipping) the peaks has the same effect.
Edit: I was assuming guitar use - it’s much more useful on bass.
Hah! I probably wouldn’t even use it on recorded dirty guitar unless it was particularly uneven playing.
It gives a certain sound on clean guitar - maybe more useful for finger picking?
It squashes loud things down and then increases the gain of everything, which has the effect of levelling everything out and making quiet stuff louder.
You don’t need it if you’re using any kind of dirt, as increasing the gain then squashing (clipping) the peaks has the same effect.
Edit: I was assuming guitar use - it’s much more useful on bass.