The ''Kennedy Center Tonight'' (produced by WQED/Pittsburgh) has proven to be a series of varied, informative, unpretentious hours of entertainment.
This week is no exception: a great jazz pioneer is shown in his triumphant appearances at the White House and at Kennedy Center: Great Vibes: Lionel Hampton & Friends (CBS Wednesday, 8-9 p.m., check local listings).
As vital and energetic as ever, Hampton is the focal point of a sparkling one-hour jam session that moves back and forth between the White House and Kennedy Center in Washington. ''Aren't we lucky to have grown up in the era of the big bands?'' says President Reagan on camera as Mr. Hampton plays on, his vibrant vibraphone taking him to strange and wonderful places. In the audience at the White House concert, the President and Mrs. Reagan beam at each other joyfully. At the Kennedy Center concert an overflow audience of jazz buffs pay tribute to a reconstituted Hampton band featuring not only Hampton but also Dave Brubeck, Louis Bellson, Illinois Jacquet, Clark Terry, Zoot Sims, and Al Grey.
Although the Hampton band still tours the nation, this joyous hour is largely nostalgia. Hampton is joined by such classic contemporary greats as Pearl Bailey , Stephanie Mills, and Betty Carter, all ''doing their thing.'' An added bonus is the vintage film clip of Hampton playing with Benny Goodman.
Produced and directed by Kip Walton, under the aegis of executive producer Dale Walton, ''Great Vibes'' is an hour of plain old/new-fashioned vibes, enjoyable even with the tinny sound produced by current-model TV sets.