Rubén Blades at the Roundhouse

A heatwave on the streets of Camden, tipping over 30 degrees. Inside the Roundhouse, the relief of air-conditioning. Until Rubén Blades took the stage, at which point the temperature soared even higher as a packed crowd welcomed the great singer, actor and sometime politician. They cheered the opening strains of “Plasticó”, from Siembre, his 1978 collaboration with Willie Colón which became the biggest selling salsa album in history, a preface to a career which has brought Blades a dozen Grammys and countless other awards, and they never let up through a 20-song set in which every member of the audience appeared to be word-perfect. As Blades observed during one of his between-songs monologues, no one is a success without the help of others, and the 20-piece band was sensational. Based in Panama City, where Blades himself was born 77 years ago to a Cuban mother and a Colombian father, and led by Roberto Delgado, the bass guitarist and arranger, they offered a widescreen version of…