Vacuum Tube - 6680 / 12AU7A, Dual Triode
New-Old-Stock (NOS) tube.
The 6680 is a medium-mu triode in the 9 pin miniature construction. It is particularly suited for use in general-purpose amplifier and phase-inverter circuits as well as for the multi-vibrator and oscillator applications.
The 6680 may be operated without serious degradation under normal variations in supply voltage as encountered with automotive electrical systems. Also, the tube will tolerate large heater voltage variations for short periods, but higher equipment reliability can be achieved with improved supply-voltage regulation. The electrical characteristics of the 6680 are equivalent to the 12AU7.