Solved where does this set item drop ?

gulliaums face.. any ides ?

 

It is in Treasure Chest (TC) 51, so starting with late nightmare and in all hell, it can drop basically anywhere.
But, given the high unique drop rate on this patch, it is way more productive to look for runes and buy it, then search for it yourself. This is from my own experience.

 

There is no point in looking for set items at the Bosses (Andariel, Travicle, Mephisto, Diablo, Nilathak and Baal) Best is to farm open areas where you may get lucky with the odd set item or high rune.

And as sphinx2 said it is TC 51 so late NM is probably your best bet.

 

There are no exact places where you can find certain items (except those who only drop from a particular boss) in D2. Your best bet is to look at item's level and work around that in order to maximize your chances of finding it. Since the helm has a level more suited for Nightmare play, then you should farm the late acts of Nightmare (IV and V).

However if you want to get technical, use this: Silospen.com

Any advice in hunting a certain item is only useful if you really want to find it yourself, if this is not really and issue, then as sphinx said trading is vital here!

There is indeed a more suffocated drop rate for set items here, because the unique one is so high. Set items are scarce, so you may find out that there are more Crown of Ages on server than Guillaume's Face!