Orchestras and pop are a tricky combination—an ensemble can overwhelm material written for a solo artist, especially when that artist trades in modest heartland tunes. But this collaborative effort from South Africa–born troubadour Gregory Alan Isakov avoids that peril. Gentle string swells buoy his rich vocals on the swooning “Saint Valentine”; tender pizzicato follows the lead of his banjo on “The Stable Song”; exquisitely warm brass drives toward a triumphant emotional climax on “Amsterdam.” Here, the symphony defers to the songs.