@asip888 A pre comes first in the chain that’s why it’s a pre. If you crank the gain on the interface it’s a lot dirtier and you’ll max it out before you get it where you want it. This is very important when it comes to vocals because you don’t want that extra noise.
@asip888 If you plug a dynamic mic directly into your interface it will be super quiet. They need a boost. I don’t have any experience with sm57’s but yes it will at the very least help enough to get going.
@asip888 If you’re trying to save as much as possible I would skip mic-ing the cab and do your guitar production in your daw. Spend the money on a better mic because vocals are a more important signal imo.