Arturo Sandoval walked into the American embassy in Rome last summer, in the midst of a European tour, and announced he was defecting from his native Cuba to the U.S.–an incident that spurred either admiration or denouncement, depending on your political leanings. But there’s a good deal less disagreement regarding Sandoval’s artistic savvy. Trained early on as a classical trumpeter, Sandoval (along with fellow emigre Paquito D’Rivera) helped form Cuba’s brilliant jazz orchestra Irakere before he branched out on his own in the 1980s; almost from the beginning, he has played the trumpet with a combination of white-hot power and swaggering dexterity that only a handful of jazzmen–Louis Armstrong, Roy Eldridge, and Dizzy Gillespie among them–have brought to the instrument. Strongly influenced by Gillespie, Sandoval can provide virtuoso soloing, while also employing the trumpet’s piercing high notes with convincing authority. But on his first American album, released this year, he also displays a previously unheard musical maturity; on several tunes, he backs off from his characteristic intensity, even to the point of using the softer, mellower flugelhorn instead of the trumpet. (This is sort of like a bullfighter putting down the cape to buy a petting zoo.) His appearance next week, with his fine new Miami-based octet, is his Chicago nightclub debut. Monday through next Saturday, May 4, Joe Segal’s Jazz Showcase, Blackstone Hotel, 636 S. Michigan; 427-4300.