Another vote for THR. Sorry that you asked for tube and some of us are suggesting the THR10 series. Frankly - you don't want a tube amp in an airstream. I have a VOX AC4HW1 and it's fabulous, but I definitely annoy my neighbours with it when I'm getting the best out of the amp - and that's in a house in suburbia. You can also use headphones with the THR10 and it sounds great. You can also use it with a cable as a phone/mp3 amplifier. Yes, it's more expensive than other amps, but I'm one of the many people who believe it's a lot better. Besides, if you're rocking an Airstream you shouldn't be worried about the cost of a THR10.