Artifact Details Title GAP/R vacuum tube K2-W Operational Amplifier Catalog Number X91.82 Type Physical object Description Two vacuum tubes occupying a single 8-pin octal socket. This packaging creates a module which forms an operational amplifier (op-amp) with differential inputs. It found wide application in analog computer designs. Date 1955 ca. Manufacturer George A. Philbrick Researches, Inc. Place Manufactured Boston, MA, US Identifying Numbers Model number GAP/R Model K2-W Other number 12AX7 Stamped on tubes Dimensions overall: 1 1/2 in x 2 in x 4 1/2 in Category Component: circuit board / module Subject Operational amplifier (op-amp); Philbrick, George Credit Gift of Thomas Turano Lot Number X91.82