In 2006, when the David Grisman Quintet released Dawg’s Groove, a couple of changes were immediately apparent: George Marsh’s drum kit filled the rhythmic space previously occupied by Joe Craven’s percussion, and the sound of Grisman’s mandolin was subtly different. A look at the cover explained the latter. Instead of his Loar F-5 (“Crusher”), Grisman cradled a rather unusually shaped mandolin. An avid collector, he’s never been shy about playing a diverse range of mandolins, especially when they support his interest in a wide array of musical genres. But this particular mandolin’s profile was a radical departure even for him.