811A

811A has no equivalent designation confirmed by the archive.

The 811A is a power triode intended for Class B audio-frequency power amplifier and modulator service. It has a thoriated tungsten filament rated at 6.3 volts AC or DC.

Construction

The tube uses a medium-shell small 4-pin Micanol base with a bayonet (JEDEC No. A4-10) and a medium cap (JEDEC No. C1-5). Maximum overall length is 6-15/32 inches, seated length is 5-11/16 inches ± 5/32 inch, and maximum diameter is 2-7/16 inches. The 811A weighs 2.7 ounces. The recommended operating position is vertical with the base down, or horizontal with pins 1 and 4 in a vertical plane.

Ratings

Maximum continuous commercial service (CCS) DC plate voltage is 1250 volts, and maximum intermittent commercial and amateur service (ICAS) DC plate voltage is 1500 volts. Maximum CCS plate dissipation is 45 watts; maximum ICAS plate dissipation is 65 watts. The tube is not recommended for oscillator service in applications involving wide variations in load.

Basing and Capacitances

Basing is: Pin 1 – filament, Pin 2 – do not use, Pin 3 – grid, Pin 4 – filament, cap – plate. Direct interelectrode capacitance from grid to plate is approximately 0.52 pF, and plate-to-filament capacitance is approximately 0.88 pF.

Original manufacturer datasheets for 811A, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• **Power Triode**