I've got a Stentor Conservatoire violin a couple of days ago and although it sounds really nice when I try to play the B note on the A string the violin "buzzes" somehow and produces a very different sound. I can assure that there's no chinrest problem, so my guess is that the strings may need too change but they seem excellent.
In that area of a violin it is common to have what is called a wolf note. You might be able to lessen it by moving the sound post. Also, you can attach a wolf note suppressor behind the bridge, but that can affect the tonal quality of that string a bit.