6AK5

6AK5 is also designated 5654, EF95. Completed sales put the typical price at $12.47 per tube.

Description

The 6AK5 is a radio-frequency voltage pentode with an indirectly heated cathode. It is an all-glass miniature tube with seven contact pins on a base type 7C10, and its bulb type is A19-1. The suppressor grid is connected internally to the cathode, which is brought out to two separate pins on the base.

Ratings and Characteristics

The filament is designed for parallel supply at 6.3 V and 175 mA. Maximum ratings include an anode voltage of 200 V, a grid No. 2 voltage of 155 V, an anode dissipation of 1.7 W, a grid No. 2 dissipation of 0.55 W, a cathode current of 20 mA, a negative grid No. 1 voltage of 50 V, a grid No. 1 circuit resistance of 0.1 MΩ, and a voltage between filament and cathode of 135 V. The grid No. 1 to anode capacitance is given as 20 pF maximum as printed, though 0.02 pF is likely intended; input capacitance is 4.0 pF and output capacitance is 2.8 pF. At Va=120 V, Vg2=120 V, and a cathode bias resistor of 200 Ω, the anode current is 7.5 mA, grid No. 2 current is 2.5 mA, transconductance is 5 mA/V, and internal resistance is 340 kΩ.

Applications

The 6AK5 is suitable for use as an IF and RF amplifier up to about 400 MHz. It can also be used in triode connection as a grounded-grid RF amplifier, mixer, or oscillator. It is specially intended for military and professional equipment, and has a reinforced internal structure for high mechanical robustness. The tube may be mounted in any position.

Construction Variants

The 5654/6AK5W variant has an oxide cathode and indirect heating, with a filament voltage of 6.3 V ±10% and a filament current ranging from 160 to 190 mA. It has an external shield of 19.25 mm inner diameter connected to the cathode. Its anode current ranges from 5 to 11 mA, grid No. 2 current from 0.8 to 4 mA, and transconductance from 3.8 to 6.2 mA/V. The grid No. 1 to anode capacitance is 0.02 pF maximum, input capacitance is 4 pF, and output capacitance is 2.85 pF. The net weight is 6 g.

Equivalence is asserted only where the archive's own literature states it directly, in at least 40 separate documents. Tubes that merely substitute in some circuits are not listed here.

Per-tube prices from completed sales, 2026-08-29 to 2026-09-15. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 6AK5, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• PENTODE DE TENSION
• 11.651 - 2.6 (filed under 5654)
• VYSOKOFREKVENČNÍ STRMÁ PENTODA (filed under EF95)

1 further designation appears alongside 6AK5 in the literature but below the evidence threshold used here, so it is not listed as equivalent.