When I was about 12, my dad built a bootleg cable descrambler out of transistors and other thingies like that, and we ended up with the full complement of 80s cable, including MTV. That was where I first heard and saw Bad Brains, in a video for “I Against I,” and the particular style of music offered by the band — totally frenetic, out-of-control, Jah-inspired DC hardcore — made me think that Dad had messed up the wiring on the his pirate cable gizmo. It was Unreal, capital ‘U.’ However many years later, the Brains are still going, recording Build a Nation, produced by Adam Yauch and released a week or so ago on Megaforce Records. And the old is new again.