You can never know what stringed instrument David Bromberg might pick up and start playing, with aplomb, at any given show. Except for the show he’s doing at The Center for Arts in Natick on Sept. 22. Though he’s an outstanding fiddler and, when he’s not on the road, is the proprietor of David Bromberg’s Fine Violins in Wilmington, Delaware, when he hits the TCAN stage, fronting his quintet, he will be fiddle-free.“I’ll bring a few guitars and [...]