Wagner, Richard: Overtures. ''Tannhauser,'' ''Rienzi,'' ''Lohengrin,'' ''Die Meistersinger.'' The Berlin Philharmonic, Klaus Tennstedt, conductor (Angel digital DS-37990). - Klaus Tennstedt is one of the few conductors Herbert von Karajan allows to record with the Berlin Philharmonic, and all of his Berlin records have been particularly interesting. Listening to the way he performs these overtures, one realizes what a loss it is that Tennstedt spends so little time in an opera house. (He does make his Met debut Dec. 14.) The ''Meistersinger'' overture is redolent of majesty, camaraderie, and life. The 'Lohengrin'' prelude is a marvel of mystery, and so the recording goes. It may not altogether erase memories of some of Karajan's Wagner disks, but it comes quite close. The only real detraction is the recorded sound, which is a bit duller and less warm than it should be.