EF86

The EF86 is a small-signal amplifier pentode vacuum tube widely used in audio equipment, particularly vintage guitar amplifiers. It is known for its relatively high gain and distinctive sonic characteristics. The EF86 was developed by Mullard in the 1950s and saw extensive use in high-fidelity audio circuits and television receivers before the widespread adoption of transistors. Its design makes it sensitive to microphonics, meaning it can pick up mechanical vibrations and convert them into audible noise, which can be both a challenge and, for some, a desirable trait contributing to its character. The tube has nine pins and operates with a 100-volt screen grid voltage, which is a key factor in its performance and tone. Common applications include preamplifier stages in amplifiers like the Vox AC15 and AC30, where its warm, harmonically rich sound is highly prized. While its use has diminished with solid-state technology, the EF86 remains a popular choice for audiophiles and guitarists seeking a vintage tube tone. Despite its age, NOS (New Old Stock) EF86 tubes are still sought after, and new production versions are also available from various manufacturers.