In 1968 the Fender amplifier line switched from the original black faceplate to a new brushed aluminum faceplate with light blue labels (except the Bronco, which has red) and changed the color of the grillcloth from silver grey to silver with sparkling blue threads embedded within it, ushering in the Silverface era. Other blackface cosmetic features were retained. The first silverface Twins used the blackface AB763 circuit until May 1968, when Fender switched to the AC568. Since the tube complement was the same, Fender just used up their stock of printed tube charts saying AB763 until they ran out.