@JeremyECrawford if you cast Chromatic Orb (has V components) while hidden, are you still hidden during the spell attack, or did the V components unhide you immediately?
— Armando Doval (@armando_doval) January 8, 2018
The rules assume that all attacks make some amount of noise, unless a particular effect says otherwise. If you're hidden and make a spell attack, follow the rule in the last paragraph of "Unseen Attackers and Targets" (PH, 194–5), whether or not the spell has a V component. #DnD https://t.co/T6MRGVvOLa
— Jeremy Crawford (@JeremyECrawford) January 8, 2018