9V-18V Four tasty, tube amp profiles with different combinations of warmth, bark, bite and attack. You can move from buttery smooth to razor sharp, but like the B-403, this box is still all about pick attack and vintage tone. It is tonally flexible, but still very transparent and responsive. The harder you drive it the more it bites. Play it clean or crank it up for that finger licking good, barbecued Texas crunch tone. It is a very dynamic box for the serious blues player.