Like Ruby Braff, Russell Gunn also has a dark tone. But while Braff is coming straight out of Louis Armstrong, trumpeter Gunn starts his journey further downstream, assimilating the lessons of Nat Adderley, Freddie Hubbard and Wynton Marsalis. On his latest, Blues on the D.L. (HighNote), Gunn is working with a strong band that hits from the first note of the opening Blue Mitchell tune, “Sir John.” Guitarist Mark Whitfield generates much heat before Gunn takes a simple riff and, with a burr and a crackle, turns it inside out in a long series of variations. Pianist Orrin Evans is especially effective on the title track, playing a block-chord solo recalling Phineas Newborn Jr. and Milt Buckner. This is a band that obviously enjoys each other’s playing, and you can hear them shout encouragement and appreciation to one another throughout. Gunn’s half-valve moaning on Miles Davis’ “No Blues” and bassist Eric Revis’ hip, angular “J.D.’s Revenge,” featuring the fine tenor work of J.D. Allen, are among the many other pleasures of this in-the-pocket set of hard-bop blues.