Telefunken ECC82(12AU7)

12AU7 is a miniature nine-pin medium-gain dual triode vacuum tube. It belongs to a large family of dual triode vacuum tubes which share the same pinout (EIA 9A). 12AU7 is also known in Europe under its Mullard-Philips tube designation ECC82. Base for this valve is B9A
The tube is popular in hi-fi vacuum tube audio as a low-noise line amplifier, driver and phase-inverter in vacuum tube push-pull amplifier circuits. There are opinions which indicate that this popularity is caused by audiophile industry/media polarization, not by its performance. [1]
The tube has a center tapped filament so it can be used in either 6.3V 300mA or 12.6V 150mA heater circuits.
Telefunken 12AU7 / ECC82 tube has long ribbed plates and a halo getter.