Bo Diddley may be one of the Model T's of electric rock 'n' roll, but it's obvious that he ran out of gas and inspiration more than 20 years ago. His career since then has been a matter of recycling his few hits, so it's little wonder that Diddley's set at the 9:30 club last night was a tedious affair, rote 'n' roll that featured some of the worst riffing Washington has seen since the Republicans took over.

Working with a pickup band after only 20 minutes of rehearsal, Diddley could little more than suggest the strengths that made him such an inspiration in the '50s--a pounding, hypnotic beat, offbeat guitar lines, bravado lyrics. The material was old--"Mona," "Who Do You Love," "Bo Diddley," "I'm a Man"--but the playing seemed even older, bored, lackadaisical. His guitar playing was emotionless, his singing little better. There was also an embarrassing recitation of legendary rock names in which Diddley did nothing to secure his own position.

The natural exuberance and raw sophistication that were evident in Diddley as recently as Richard Nader's late-'60s rock 'n' roll revues have been replaced by incipient boredom. At 53, Diddley's place in rock history may be secure enough for him to risk offending fans who know better and new audiences who don't, but that doesn't excuse the deplorable rendering of that history last night.

Local rockabilly revivalists, the Bob E. Rock Band, opened with an exuberant set full of hiccups, whoops and hollers. The sound was delightfully lean and one felt more genuine enthusiasm in their secondhand recitations than in a single Diddley number. For them, at least, there was still an element of surprise in the flow of raucous melodies.