The Facebook banner used by Sanz Trio looks like a billboard on Hollywood Boulevard. Huge letters spell out the band name against an electric gold background. It’s big, showy and loud. The artwork is fitting for a band that calls itself a “musical trio of all-stars” and “Duluth’s top blues/jam rock band.” Formed spontaneously to open for local reggae band Revolution Jones, Sanz Trio has spent the past few years tightening up its sound and writing original blues rock material. The group is led by singer and guitarist Josh Nickila with Scott Millis on drums and Brian Wells on rhythm.