What happens to /v/ when it's immediately followed by /b/ in American English?

In phrases like "of books" "have been" and more what happens to that /v/ sound i tried listening online but I can’t quite place how exactly it is made. Does it get devoiced or get changed into a plosive? And a more general question: What happens in the consonant clusters xy where x is a front fricative sound and y is a front plosive sound

edit: would this be correct: of books: ʌbˈbʊks