1. The 7AU7 is a miniature dual-diode vacuum tube that was once used in all types of electronic equipment, including televisions, radios, receivers, and amplifiers.
2. It is distinguished by its small size, consisting of a single side panel with two diodes and a socket for the anode connection.
3. The 7AU7 can be used for voltage regulation, audio frequency amplification, and many other functions.
4. It is suitable for medium-power applications, making it a great choice for relatively low-power audio amplifiers and other devices.
5. Today, the 7AU7 is still made and can be found in a variety of vintage gear and modern-day grid-biased audio amplifiers.
6. We highly recommend inspecting and testing the 7AU7 before using it because it's an older tube and may not last long if it's not cared for properly.
7. The 7AU7 is also popular for its low cost and plentiful availability.