The Tektronix H074A (P/N 155-0064-00) is a vertical output amplifier hybrid integrated circuit in a 12-pin TO-8 stud mounted can, developed by Tektronix in the early 1970s.
Maximum power dissipation is 4 watts. Rise time is specified as 470 ps (equiv. bandwidth 745 MHz).
It is the same as the 155-0065-00 (H074), except for the case stud and specified pin 3 to case breakdown voltage.
There is also an H074B (155-0125-00) version.
According to Modification 050-1014-00, Vertical Output Microcircuit Replacement, the emitter resistors need to be selected according to a code printed on the device.