Hi!
Are you referring to MBB? If yes, then the answer is no - there is absolutely no difference. The interviews are identical. The offer letter will differ however, since a junior associate is a slightly more senior position then a BA (at McKinsey!).
Moreover, you have to understand that "knowledge" is not tested in MBB intervews! What they are testing is your intrinsic ability to think in a sharp and structured way, clearly articulate this thinking, execute the corresponding analyses, and derive recommendations for the client. All of this doew not require any "knowledge" per se, just a set of capabilities. And this is what MBB are testing for - capabilities!
Cheers, Sidi
Yes I was referring to MBB, thank you very much for the fast response!