had not vs did not - past perfect [closed]

The sentence He did not study music before he became famous is correct, but it is not written in the past perfect. You used the past simple. You used 'did' because the sentence is a negation.

Small guide on the difference between the past simple, present perfect and past perfect:

• The past simple is used when something is over and done with, i.e. it has no relevant influence on the present. It is usually used if the sentence contains yesterday, a week ago, last year, etc.
• The present perfect is used when something started in the past and is still going on, or when it has relevant influence on the present.
• The past perfect is almost always used in combination with other verbs, to indicaste that something in the past happened and had influence on the actions described by the other verbs. This is a bit difficult, so I will explain it with your example sentence: He had not learnt music before he became famous. In this case, the fact that he had not learnt music was relevant at the time when he became famous.

The difference between He had not learnt music before he became famous and He did not study music before he became famous is that in the first sequence you indicate that the fact that he had not learnt music had influence for some reason you explain later.