I've asked this before but not sure if I've got a proper answer.

My Ukrainian study guide says in standard Ukrainian pronunciation, a В is pronounced like English W at the end of a word and before a consonant.

Now I clearly here it at the end of the word.

Знав - Znaw

But before consonants I still here V.

Вівторок sounds like vivtorok to me and not viwtorok.

Is it that certain areas pronounce it W before a consonant and others don't? I know if the East, they may always say V even at the end of the word.