Electric-blues revivalists and southern rockers clog the nation's nightclubs, aimlessly jamming and giving lead-footed beer drinkers a chance to dance. North Mississippi Allstars runs on that same well-beaten track, but last year's debut album Shake Hands With Shorty saw the group setting the pace, and its sophomore release 51 Phantom maintains a good deal of that momentum. Twenty-eight-year-old guitarist Luther Dickinson, drummer Cody Dickinson (Luther's younger brother), and bassist Chris Chew use earthy, traditional blues arrangements as a context for focused, energized instrumental improvisation. Shorty's dewy Delta authenticity emerges not just from the Dickinsons' pedigree as the sons of Memphis producer Jim Dickinson, or from the presence of the songs and spiritual progeny of blues journeyman R.L. Burnside. It comes from Luther Dickinson, an astonishingly fluid musician who bounces around in the flexible net provided by his rhythm section, hopping from thick roots-rock grooves to frenzied, punk-inspired guitar work. Reference 51 Phantom's "Sugartown," which circles around a fat, heavy blues riff for about a minute before surging forward to a whipcrack pace, covered by a windstorm of guitar noise, which Dickinson creates with ecstatic bliss. Not every track on the new record or on Shorty has one of those good-to-be-alive, breath-of-fire momentsand even if they do, they often arrive just after the album emerges from a blues-rock grinder. Much of 51 Phantom sounds derivative of ZZ Top, and not the furious Tres Hombres/Fandango Top, but the arid El Loco edition. The dryness can be partly attributed to the Dickinson brothers' first recorded attempts at songwriting, and partly to the production of father Jim, who applies more polish than his kids did on their self-produced debut. But North Mississippi Allstars isn't about innovation. In the great blues-ensemble tradition, its members wait for the chance to play serve-and-volley with their instruments, and drag the audience into their mood. Every track on 51 Phantom is steeped in such anticipation, and the promise of fireworks surrounds every chorus.