Now he’s back in L.A. Last Call, his initial outing for Delta Groove Productions, mostly eschews a tough blues sound for the sophistication of jazz and 1940s and 1950s R&B. It’s an intriguing concept that will play well for those seeking a late-night retro mood, though others might find the cool vibe a bit restrained. Last Call benefits from marvelous supporting players, including Kid Ramos (who plays guitar on “Well Alright, O.K., You Win”), Rich DelGrosso on mandolin, and Armando Cortez, who contributes a deliciously nasty guitar part to “Say It,” one of the album’s most exhilarating tracks. With its lights-down-low atmosphere and slick groove, it delivers an urgency that cuts through the detached air prevailing elsewhere.

Though most of the recording is given over to well-chosen covers of relatively obscure material (“I’m Tired,” written by guitar legend Mickey Baker, is a highlight), Slim proves a fine writer on “You’re a Pain,” which evinces a hangdog sense of humor that keeps with the disc’s ironic tone. ”Across the Sea,” another self-composition, is a terrific showcase for his juicy harmonica. The album could have benefited from more harp; it would be interesting to hear how Slim’s playing might fit into the disc_s jazzy atmosphere of experimentation. But on the whole, Last Call is respectful and pleasing, even as it keeps its emotions firmly in check.