EC91 6AQ4 Mullard

Description

Precision RF Amplifier Triode
The Mullard EC91, also designated 6AQ4, is a miniature triode vacuum tube developed for radio-frequency amplification and oscillator roles in compact electronics. It saw extensive use in military communications, signal generators, and FM tuners throughout the mid-20th century. Because of its dependable performance, it remains a favored component in restorations and high-frequency circuit builds.

Stable and Clean Signal Handling
The EC91 operates efficiently as an oscillator or RF amplifier, providing consistent gain with minimal internal noise. This ensures precise signal reproduction and frequency stability, even in sensitive RF environments. Moreover, Mullard’s meticulous engineering enhances thermal behavior and minimizes microphonics. In addition, the tube supports strong signal integrity over long operating periods. As a result, engineers and restorers benefit from both stability and clarity.

Compact Format, Broad Compatibility
Housed in a slender glass envelope with a B7G 7-pin base, the EC91 installs easily in tight chassis layouts. Therefore, it is ideal for vintage field radios, lab equipment, and FM front ends where space-saving design is critical. Furthermore, it directly replaces equivalents like 6AQ4 and CV138, making it highly versatile. Whether you’re restoring test equipment or building a fresh RF stage, this tube integrates seamlessly.

Mullard Quality and Durability
Mullard is well-known for manufacturing tubes with exceptional reliability and long service life. The EC91 continues that tradition with rugged construction and tightly controlled tolerances. Additionally, it resists vibration and heat fluctuations, maintaining performance even in demanding conditions. Thanks to this durability, the tube serves equally well in both active devices and collector-grade gear.

Excellent Choice for RF Projects
Whether you’re rebuilding vintage communications gear or assembling a high-frequency test rig, the Mullard EC91 offers clean signal response, long-term reliability, and authentic period-correct quality. Choose this tube for trusted Mullard craftsmanship and proven performance in RF applications.