ok so this is a no fail method.
Keep feeding bloodworms but throw in the whole frozen cube. once he eats the cube whole you got him.
Take a tray of bloodworm cubes pop them all out and defrost them in your favorite cereal bowl. mix in your pellet of choice 15 percent to start, mix and spread mixture back into bloodworm tray, refreeze. pop out a couple and feed bass. he will take it. then make higher percentage pellet to worm cubes and continue to feed. soon he will be wacking pellets. Be forwarned as to one of my other threads. It may make your fish a little, how do you say, fond of the male bass with the big hump.
the other element that helps is competition, or more bass. this makes the process even easier.