The evolution continues: sometime during the day yesterday, KCBS switched to a new set of jingles. This is the second major switch since I moved to the Bay Area in 1989, but they’ve managed to keep the same four-note sequence as the major theme over the years. Also, back in October or November, KCBS eliminated the previews of upcoming news stories after CBS News at the top of the hour. Think I’m obsessive about this? Well, I am, but I’m not the only one. For instance, TV Ark has dozens of video clips of TV channel promos, including American channels.