The 6680 / 12AU7A Vacuum tube is a miniature type used as
phase inverters or push-pull
amplifiers in AC/DC radio equipment and as
multivibrators or oscillators in industrial control
devices. They are also used as combined vertical
oscillators, vertical-deflection amplifiers, and as
horizontal-deflection oscillators in TV receivers.
These tubes are also used in headphone preamplifiers.
They require a miniature 9-contact socket.
Electrical Data:
Heater Voltage ................. 6.3/12.6 V
Heater Current ................. 0.3/0.15 A
Preferred Substitutes .............. 12AT7
Substitutes .................. 12AZ7 12BH7