Thanks Cameron and Chris.
But wouldn't some of them just jump from zero to too loud? For example, I actually bought a 20w Laney praccy amp which jumps from low, farty sound to a nice sound that is about the loudest I'd want to play in my flat. My Ashdown LB30 has a better sound at low volume levels - but again, there's not much room to play with here. Although a gain on the Ashdown would definitely help.