Last night the San Francisco Conservatory of Music Concert Hall saw the annual Distinguished Artist Series recital for the American Bach Soloists (ABS) Festival 2015. The featured soloist was John Thiessen, performing on baroque trumpet. He was joined by soprano Kathryn Mueller and seven of his ABS colleagues. The program divided into five Italian baroque composers for the first half and three works from the English baroque in the second. ABS performers provided chamber music “spacers” between Thiessen’s selections.