Involved in the biosynthesis of the antifungal agent validamycin A (PubMed:16725283). Catalyzes the dephosphorylation of validoxylamine A 7'-phosphate to yield validoxylamine A (PubMed:21766819). VldH is also able to convert trehalose 6-phosphate to trehalose (PubMed:21766819). H2O + validoxylamine A 7'-phosphate = phosphate + validoxylamine A Requires the presence of a divalent metal cation for activity. Can use magnesium, manganese or cobalt. Belongs to the HAD-like hydrolase superfamily. CbbY/CbbZ/Gph/YieH family.