6AQ8

6AQ8 is also designated ECC85. Completed sales put the typical price at $26.68 per tube.

Description

The 6AQ8 is a double triode with two electrically identical systems, high transconductance, medium amplification factor, and separate cathodes. It has an all-glass miniature envelope with a nine-pin base. The two systems are independent and separated by internal shielding; all electrodes including the shield are brought out to the base pins. The tube has indirect heating with an oxide cathode and parallel AC supply.

Ratings

The heater requires 6.3 V at 0.435 A. Per section, the maximum plate voltage is 300 volts, the maximum plate voltage without current is 550 volts, and the maximum plate dissipation is 2.5 watts; the maximum plate dissipation of both sections together is 4.5 watts. The maximum cathode current is 15 mamps, the maximum negative grid bias is 100 volts, the maximum external resistance between grid and cathode is 1 megohm, and the maximum voltage between cathode and heater is 90 volts.

Characteristics

The typical amplification factor of each section is 57. Capacitance values, measured with an external shielding can of 0.886 inches diameter, are: maximum plate-to-cathode capacitance of triode section 2 is 0.18 μμF, maximum grid-to-cathode capacitance of triode section 2 is 3.0 μμF, and maximum plate-to-cathode capacitance of triode section 2 is 1.2 μμF. Between sections, the maximum plate-to-plate capacitance is 0.04 μμF, the maximum grid-to-grid capacitance is 0.003 μμF, and the maximum plate-to-grid capacitance is 0.008 μμF.

Applications

The 6AQ8 is suitable for use as an RF amplifier or mixer with self or external excitation in quality radio receivers for FM and television signal reception. It is a replacement for the foreign type 6AQ8.

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, 2026-03-02 to 2026-09-19. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 6AQ8, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• 6AQ8
• Charakteristické hodnoty: (filed under ECC85)

4 further designations appear alongside 6AQ8 in the literature but below the evidence threshold used here, so they are not listed as equivalent.