Electro Harmonix 12AU7EH Vakuumrør

A clean, low-gain twin triode

The Electro-Harmonix 12AU7 handles the jobs where an amplifier needs control rather than gain. Its low amplification factor makes it a natural fit for line stages, cathode followers, phase inverters and driver positions ahead of the output tubes, where the priority is passing the signal on intact. In hi-fi preamplifiers the same character keeps the presentation open and uncoloured.

Built as a reproduction of the GE 6189

Electro-Harmonix designed this tube around the classic NOS GE 6189, and the two qualities it is built for are low microphonics and high linearity. Low microphonics matter in preamp positions close to a speaker, where a ringing tube turns into audible noise; high linearity keeps distortion down when the tube is simply passing signal along. Plate dissipation is 2.75 W per triode.

Where it fits

Because it is a true ECC82 equivalent, the 12AU7 goes into any socket specified for that family without modification. Electro-Harmonix tubes are current production rather than old stock, built in Russia, and the company supplies many amplifier manufacturers with relabelled versions of the same tubes. This item is a single tube.