Too many years have passed since Randy Sabien’s violin last lit up Chicago. When Sabien first came on the scene he seemed to merge the two classic schools of jazz violin playing; although he descends more from the gritty boisterousness of Joe Venuti, he stiff brings intimations of Stephane Grappelli’s elegant French precision to his technique. These days other violinists have been able to similarly fuse these two approaches and even incorporate a more modern strain; but the ranks of swinging and accomplished jazz fiddlers remain thin, and Sabien surely belongs up near the front. Sabien boasts a full-bodied tone equally suited to folk forms like bluegrass–a tone so strong that he can revel in it, in much the way classic jazz tenormen indulged a ballad or manipulated a rocking blues. (Oddly enough another noteworthy violinist, Regina Carter, also plays Chicago this weekend, coleading the band Straight Ahead at the Cotton Club; any chance of a late-night bowing session?) Sabien appears with a gang of sidemen better known for their participation on public radio’s Saturday-morning hit Whad’ Ya Know?: pianist John Thulin, bassist Jeff Eckels, and drummer Clyde Stubblefield–all old friends from Sabien’s days in Madison. Tonight, 9 PM, Bop Shop, 1807 W. Division; 235-3232.