I'm looking to buy an amp for my son and was thinking that maybe I should buy him something like a combo tube amp that he can grow into. I looked at all the entry level amps which are very cool but I think he's gonna need something a little more powerful in the future. My question is how do you get the heavy crunchy sound without it built into the amp? Do you use pedals for that? I just figured I would look for something used that he could use for a long time. Any recommendations on what I should look for?