A minor medical emergency waylaid my plan to catch a concert by Little Feat last week. I took solace in the third installment of Tedeschi Trucks Band’s I Am the Moon. The first three portions of the four-part series validate my belief that the ensemble is the premier jam band of the past 15 years. Between the well-constructed songs, Tedeschi’s soulful voice and succinct guitar shredding, I Am the Moon III: The Fall compares favorably with the most durable hippie jams by the likes of the Allman Brothers Band, Traffic and, of course, Little Feat.