12AQ5 Vacuum Tube – Sylvania NOS – New Pentode

The 12AQ5 vacuum tube by Sylvania (NOS) is a beam power pentode with a 7-pin miniature base (B7G). It is electrically identical to the 6AQ5, with the only difference being its filament designed to operate at 12.6 volts. Manufactured by Sylvania in the United States, this valve stands out for its reinforced internal construction and its ability to deliver crystal-clear audio with the “soft” harmonic distortion characteristic unique to vacuum tubes.

Brand History: Sylvania

Sylvania Electric Products was, for decades, the gold standard in vacuum tube manufacturing in the United States. Its facilities in Emporium, Pennsylvania, produced some of the most reliable tubes for military and broadcasting applications. Owning a “Yellow Label” Sylvania tube or one in its original box is a guarantee of superior engineering, high-purity materials, and extended service life.

Common Applications

• Hi-Fi Audio & Guitar: Used in single-ended output stages for practice amplifiers or high-end headphone amplifiers.

• Radio Restoration: Essential for vintage car radios (12V systems) and “boat anchor” communication receivers.

• DIY Projects: Ideal for amateur radio QRP transmitters due to its compact size and efficiency.

Technical Specifications – 12AQ5 Vacuum Tube (Sylvania NOS)

• Type: Beam Power Pentode

• Heater Voltage: 12.6 V (AC/DC)

• Heater Current: 0.225 A

• Maximum Plate Voltage: 250 V

• Plate Dissipation: 12 W

• Base: 7-pin miniature (B7G, heptal)

• Typical Configuration: Class A1 or Push-Pull Class AB1

(FAQ)

Is the 12AQ5 compatible with the 6AQ5?
They are electrically identical in terms of operating characteristics and curves, but they are not directly interchangeable because the 12AQ5 requires a 12.6V heater, while the 6AQ5 requires 6.3V.

What does “NOS” mean in this Sylvania tube?
It stands for New Old Stock. This refers to a component manufactured decades ago that has never been used and remains in its original factory packaging.

How has this tube been tested?

It has been verified on a professional tube tester, confirming that cathode emission levels and the absence of internal shorts are within factory specifications.